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Sample records for active auroral research

  1. An Electromagnetic Interference Study of Potential Transmitter Sites for the HF Active Auroral Research Program (HAARP)

    DTIC Science & Technology

    1993-07-19

    heating . The measurements described in this report were conducted at a number of candidate HAARP transmitter sites in the vicinity of Fairbanks...employ the High Power Auroral Stimulation (HIPAS) RF heating facility [1], located in the Chena River valley area near Fairbanks. HAARP will be an...Potential Transmitter Sites for the HF Active Auroral Research Program ( HAARP ) JOSEP11 A. GOLDSTEIN EDWARD 1. KENNEDY ADRIAN S. ELEY 4 IMICHlAEL A. RuPAR C

  2. Upper atmospheric effects of the hf active auroral research program ionospheric research instrument (HAARP IRI)

    SciTech Connect

    Eccles, V.; Armstrong, R.

    1993-05-01

    The earth's ozone layer occurs in the stratosphere, primarily between 10 and 30 miles altitude. The amount of ozone, O3, present is the result of a balance between production and destruction processes. Experiments have shown that natural processes such as auroras create molecules that destroy O. One family of such molecules is called odd nitrogen of which nitric oxide (NO) is an example. Because the HAARP (HF Active Auroral Research Program) facility is designed to mimic and investigate certain natural processes, a study of possible effects of HAARP on the ozone layer was conducted. The study used a detailed model of the thermal and chemical effects of the high power HF beam, which interacts with free electrons in the upper atmosphere above 50 miles altitude. It was found only a small fraction of the beam energy goes into the production of odd nitrogen molecules, whereas odd nitrogen is efficiently produced by auroras. Since the total energy emitted by HAARP in the year is some 200,000 times less than the energy deposited in the upper atmosphere by auroras, the study demonstrates that HAARP HF beam experiments will cause no measurable depletion of the earth's ozone layer.... Ozone, Ozone depletion, Ozone layer, Odd nitrogen, Nitric oxide, HAARP Emitter characteristics.

  3. Mapping auroral activity with Twitter

    NASA Astrophysics Data System (ADS)

    Case, N. A.; MacDonald, E. A.; Heavner, M.; Tapia, A. H.; Lalone, N.

    2015-05-01

    Twitter is a popular, publicly accessible, social media service that has proven useful in mapping large-scale events in real time. In this study, for the first time, the use of Twitter as a measure of auroral activity is investigated. Peaks in the number of aurora-related tweets are found to frequently coincide with geomagnetic disturbances (detection rate of 91%). Additionally, the number of daily aurora-related tweets is found to strongly correlate with several auroral strength proxies (ravg≈0.7). An examination is made of the bias for location and time of day within Twitter data, and a first-order correction of these effects is presented. Overall, the results suggest that Twitter can provide both specific details about an individual aurora and accurate real-time indication of when, and even from where, an aurora is visible.

  4. Adam Paulsen, a Pioneer in Auroral Research

    NASA Astrophysics Data System (ADS)

    Jørgensen, Torben S.; Rasmussen, Ole

    2006-02-01

    The 20 to 30 years following the first International Polar Year in 1882-1883 was a period of quickly advancing knowledge and understanding of auroral phenomena. This was the time when hypotheses of aurora being due to, for example, reflections of fires from the interior of the Earth or sunlight from ice particles were abandoned and replaced by the mechanism of precipitating electrons. One of the auroral researchers at that time was the Dane Adam Frederik Wivet Paulsen (1833-1907). However, when reading literature about auroral history, his ideas and work do not seem to have attracted much interest outside his own and neighboring countries. For example, in his sweeping historical account Majestic Lights: The Aurora in Science, History, and the Arts [1980], author Robert Eather only referred to Paulsen in a couple of lines.

  5. The Utility of Auroral Image-based Activities Metrics

    NASA Technical Reports Server (NTRS)

    Germany, G.; Spann, J.; Deverapalli, C.; Hung, C.-C.

    2004-01-01

    Auroral activity indices such as Hemispheric Power and Auroral Boundary are currently key data products used for space weather predictions and nowcasting. However, these products are necessarily based on limited observations which must be extrapolated to provide global coverage. The advent of routine space-based auroral imaging in the last decade offers the seeming advantage of more detailed measures of auroral activity. Examples of image-derived products include energy deposition maps, oval location, cap size, and morphological classification. However, activity metrics derived from auroral images have shortcomings, as well. For example, limited fields-of-view and orbital motion prevent full coverage of the auroral regions. This paper will examine the utility of activity metrics derived h m auroral images for operational purposes. The eight-year collection of Polar UVI images databased in the UVI Online Search Tool (OST) will be used to illustrate the advantages and shortcomings of auroral activity metrics. The potential role of other currently-active imaging missions will also be examined and correlative studies to date using auroral imaging will be summarized.

  6. Sophus Peter Tromholt: an outstanding pioneer in auroral research

    NASA Astrophysics Data System (ADS)

    Moss, K.; Stauning, P.

    2012-03-01

    The Danish school teacher Sophus Peter Tromholt (1851-1896) was self-taught in physics, astronomy, and auroral sciences. Still, he was one of the brightest auroral researchers of the 19th century. He was the first scientist ever to organize and analyse correlated auroral observations over a wide area (entire Scandinavia) moving away from incomplete localized observations. Tromholt documented the relation between auroras and sunspots and demonstrated the daily, seasonal and solar cycle-related variations in high-latitude auroral occurrence frequencies. Thus, Tromholt was the first ever to deduce from auroral observations the variations associated with what is now known as the auroral oval termed so by Khorosheva (1962) and Feldstein (1963) more than 80 yr later. He made reliable and accurate estimates of the heights of auroras several decades before this important issue was finally settled through Størmer's brilliant photographic technique. In addition to his three major scientific works (Tromholt, 1880a, 1882a, and 1885a), he wrote numerous short science notes and made huge efforts to collect historical auroral observations (Tromholt, 1898). Furthermore, Tromholt wrote a large number of popular science articles in newspapers and journals and made lecture tours all over Scandinavia and Germany, contributing to enhance the public educational level and awareness. He devoted most of his life to auroral research but as a self-taught scientist, he received little acclaim within the contemporary academic scientific society. With his non-academic background, trained at a college of education - not a university - he was never offered a position at a university or a research institution. However, Sophus Tromholt was an outstanding pioneer in auroral research.

  7. A study of auroral activity in the nightside polar cap

    SciTech Connect

    Wu, Q.

    1989-01-01

    Using various ground observations at South Pole, Antarctica (invariant magnetic latitude -74{degree}) and its conjugate point, Frobisher Bay, Canada, the author has studied the following aspects of nightside polar cap auroral activity: the appearance and disappearance of polar cap auroras (diffuse and discrete) associated with substorms and interplanetary magnetic field (IMF) variations; auroral optical emission line intensities; and the seasonal variation of auroral conjugacy. The observations show that the polar cap auroras usually fade away before the expansive phase of a substorm and bright auroral arcs reach high latitude (-74{degree}) near the recovery phase. Just before the auroras fade away the discrete polar cap auroral arcs, which are usually on the poleward boundary of the diffuse aurora, intensify for 1 to 2 minutes. The observations also indicate the IMF may have stronger control over polar cap auroral activity than do substorms. A search for energy spectral variation of precipitating electrons using the intensities of 630.0 nm (0) and 427 nm (N{sub 2}{sup +}) auroral emission lines reveals no dramatic changes in the energy spectrum; instead, the data show possible atmospheric scattering and geometric effects on the photometric measurements while the bright auroral arc is moving into the polar cap. The conjugate observations show that the stormtime auroral electrojet current, which is associated with the bright auroral arc, in most cases reaches higher (lower) latitudes in the winter (summer) hemisphere. An asymmetric plasma sheet (with respect to the neutral sheet) is proposed, which expands deeper into the winter lobe, under a tilted geomagnetic dipole. Accordingly, the winter polar cap would have smaller area and the auroral electrojet would be at higher latitude.

  8. Exploring HF-induced ionospheric turbulence by Doppler sounding and stimulated electromagnetic emissions at the High Frequency Active Auroral Research Program heating facility

    NASA Astrophysics Data System (ADS)

    Sergeev, Evgeny N.; Shindin, Alexey V.; Grach, Savely M.; Milikh, Gennady M.; Mishin, Evgeny V.; Bernhardt, Paul A.; Siefring, Carl L.; Briczinski, Stanley J.; McCarrick, Michael J.

    2016-07-01

    We report on the features of the F region plasma perturbations during HF heating experiments at the High Frequency Active Auroral Research Program facility in March-April 2011 and May-June 2014. The diagnostics included multifrequency Doppler (phase) sounding (MDS) and stimulated electromagnetic emission (SEE). The results concern modification of the electron density profile near the reflection and upper hybrid heights, as well as correlation of the density modification with temporal behavior of narrow continuum, downshifted maximum, and broad continuum SEE spectral features. We reveal also a new SEE spectral feature which appears in the SEE spectra for the pump frequency f0 near the third and fourth electron gyroharmonics. It is located in the SEE spectrum well below the pump wave frequency, f - f0 -(40-220) kHz, occupies a wide frequency range till 100-150 kHz, and is termed the broad downshifted emission.

  9. Dayside Auroral Activity During Solar Maximum and Minimum Periods

    NASA Astrophysics Data System (ADS)

    Rawie, M.; Fasel, G. J.; Flicker, J.; Angelo, A.; Bender, S.; Alyami, M.; Sibeck, D. G.; Sigernes, F.; Lorentzen, D. A.; Green, D.

    2014-12-01

    It is well documented that the dayside auroral oval shifts equatorward when the interplanetary magnetic field (IMF) Bz-component turns southward [Burch, 1973; Akasofu, 1977; Horwitz and Akasofu, 1977; Sandholt et al., 1986, 1988]. During these periods of oval expansion dayside transients are observed to move away from the poleward edge of the auroral oval and drift poleward. These poleward-moving auroral forms are believed to be ionospheric signatures of dayside merging. The dayside auroral oval usually begins to contract when the interplanetary magnetic field turns sharply northward, Bz>0. Eighteen years of meridian scanning photometer (MSP) data from the Kjell Henriksen Observatory in Longyearbyen, Norway are analyzed. During the boreal winter the Sun is several degrees below the horizon. This permits optical observations throughout the daytime period. The MSP Data is selected two hours before and after local noon in Longyearbeyn. Solar wind data (solar wind pressure and speed, along with the IMF Bx, By, Bz components) are collected for each interval and combined with the MSP observations. This data is then separated using solar maximum and minimum periods. Auroral activity (oval expansions and contractions along with the frequency and number of poleward-moving auroral forms) is documented for both solar maximum and minimum periods.

  10. Relative Order of Auroral Transient Structure During Substorm Activation

    NASA Astrophysics Data System (ADS)

    Kozelov, B. V.; Rypdal, K.

    2007-12-01

    Variability of auroral structures is a manifestation of the magnetosphere-ionosphere plasma dynamics. During the last decade the complexity of magnetosphere-ionosphere plasma has been widely discussed in numerous papers. The most popular approaches are based on turbulence or/and self-organized criticality paradigms. However, there is no clear evidence that the dynamics during the discussed events is really organization, and not disorganization. The problem is that the magnetosphere-ionosphere system is an open non-equilibrium system, therefore classical thermodynamics is not directly applicable. Here we use an approach based on the S-theorem by Yu.L. Klimontovich. This approach allows us to compare the ordering which characterize the current (non- equilibrium) state of the system with experimental data. The considered characteristic is an analogy of entropy which has been extended to non- equilibrium states. Television observations of the auroral structure during substorm activation at the Barentsburg observatory (Svalbard) have been used as a data set. Dependence of the ordering on the spatial scale has been analyzed. We found that the ordering of the aurora increases during the substorm development. The same approach has been applied to data sets generated by cellular automata models. Evolution of the systems in time and dependence on external control parameters are compared and discussed. Acknowledgements. This work was supported by grant No 171076/V30 of the Norwegian Research Council and partly by the Division of Physical Sciences of Russian Academy of Science.

  11. Solar wind control of auroral zone geomagnetic activity

    NASA Technical Reports Server (NTRS)

    Clauer, C. R.; Mcpherron, R. L.; Searls, C.; Kivelson, M. G.

    1981-01-01

    Solar wind magnetosphere energy coupling functions are analyzed using linear prediction filtering with 2.5 minute data. The relationship of auroral zone geomagnetic activity to solar wind power input functions are examined, and a least squares prediction filter, or impulse response function is designed from the data. Computed impulse response functions are observed to have characteristics of a low pass filter with time delay. The AL index is found well related to solar wind energy functions, although the AU index shows a poor relationship. High frequency variations of auroral indices and substorm expansions are not predictable with solar wind information alone, suggesting influence by internal magnetospheric processes. Finally, the epsilon parameter shows a poorer relationship with auroral geomagnetic activity than a power parameter, having a VBs solar wind dependency.

  12. Jovian ultraviolet auroral activity, 1981-1991

    NASA Technical Reports Server (NTRS)

    Livengood, T. A.; Moos, H. W.; Ballester, G. E.; Prange, R. M.

    1992-01-01

    IUE observations of H2 UV emissions for the 1981-1991 period are presently used to investigate the auroral brightness distribution on the surface of Jupiter. The brightness, which is diagnostic of energy input to the atmosphere as well as of magnetospheric processes, is determined by comparing model-predicted brightnesses against empirical ones. The north and south aurorae appear to be correlated in brightness and in variations of the longitude of peak brightness. There are strong fluctuations in all the parameters of the brightness distribution on much shorter time scales than those of solar maximum-minimum.

  13. Electromagnetic interference impact of the proposed emitters for the High Frequency Active Auroral Research Program (HAARP). Interim report

    SciTech Connect

    Robertshaw, G.A.; Snyder, A.L.; Weiner, M.M.

    1993-05-14

    The proposed HAARP emitters at the Gakona (Alaska) preferred site and at the Clear AFS (Alaska) alternative site are the Ionospheric Research Instrument (IRI), the Incoherent Scatter Radar (ISR), and the Vertical Incidence Sounder(VIS). The electromagnetic interference (EMI) impact of those emitters on receiving systems in the vicinity of the sites is estimated in this study. The results are intended for use as an input to the Air Force Environmental Impact Statement as part of the Environmental Impact Analysis Process.

  14. Approximating ambient D-region electron densities using dual-beam HF heating experiments at the high-frequency Active Auroral Research Program (HAARP)

    NASA Astrophysics Data System (ADS)

    Agrawal, Divya

    Dual-beam ELF/VLF wave generation experiments performed at the High-frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska are critically compared with the predictions of a newly developed ionospheric high frequency (HF) heating model that accounts for the simultaneous propagation and absorption of multiple HF beams. The dual-beam HF heating experiments presented herein consist of two HF beams transmitting simultaneously: one amplitude modulated (AM) HF beam modulates the conductivity of the lower ionosphere in the extremely low frequency (ELF, 30 Hz to 3 kHz) and/or very low frequency (VLF, 3 kHz to 30 kHz) band while a second HF beam broadcasts a continuous waveform (CW) signal, modifying the efficiency of ELF/VLF conductivity modulation and thereby the efficiency of ELF/VLF wave generation. Ground-based experimental observations are used together with the predictions of the theoretical model to identify the property of the received ELF/VLF wave that is most sensitive to the effects of multi-beam HF heating, and that property is determined to be the ELF/VLF signal magnitude. The dependence of the generated ELF/VLF wave magnitude on several HF transmission parameters (HF power, HF frequency, and modulation waveform) is then experimentally measured and analyzed within the context of the multi-beam HF heating model. For all cases studied, the received ELF/VLF wave magnitude as a function of transmission parameter is analyzed to identify the dependence on the ambient D-region electron density (Ne) and/or electron temperature ( Te), in turn identifying the HF transmission parameters that provide significant independent information regarding the ambient conditions of the D-region ionosphere. A theoretical analysis is performed to determine the conditions under which the effects of Ne and Te can be decoupled, and the results of this analysis are applied to identify an electron density profile that can reproduce the unusually high level of ELF

  15. Joseph Henry and John Henry Lefroy A common 19th century vision of auroral research

    NASA Astrophysics Data System (ADS)

    Silverman, S. M.

    Research on solar-terrestrial relationships today relies primarily on in situ space data. These data, however, cover only a short period of about 30 years. Many solar and related phenomena vary on much longer time scales. For the study of these, parameters such as sunspots, magnetic activity, auroral occurrence, or other proxy data are required. Historical records of aurora are particularly useful in this connection.

  16. Danish auroral science history

    NASA Astrophysics Data System (ADS)

    Stauning, P.

    2011-01-01

    Danish auroral science history begins with the early auroral observations made by the Danish astronomer Tycho Brahe during the years from 1582 to 1601 preceding the Maunder minimum in solar activity. Included are also the brilliant observations made by another astronomer, Ole Rømer, from Copenhagen in 1707, as well as the early auroral observations made from Greenland by missionaries during the 18th and 19th centuries. The relations between auroras and geomagnetic variations were analysed by H. C. Ørsted, who also played a vital role in the development of Danish meteorology that came to include comprehensive auroral observations from Denmark, Iceland and Greenland as well as auroral and geomagnetic research. The very important auroral investigations made by Sophus Tromholt are outlined. His analysis from 1880 of auroral observations from Greenland prepared for the significant contributions from the Danish Meteorological Institute, DMI, (founded in 1872) to the first International Polar Year 1882/83, where an expedition headed by Adam Paulsen was sent to Greenland to conduct auroral and geomagnetic observations. Paulsen's analyses of the collected data gave many important results but also raised many new questions that gave rise to auroral expeditions to Iceland in 1899 to 1900 and to Finland in 1900 to 1901. Among the results from these expeditions were 26 unique paintings of the auroras made by the artist painter, Harald Moltke. The expedition to Finland was headed by Dan la Cour, who later as director of the DMI came to be in charge of the comprehensive international geomagnetic and auroral observations made during the Second International Polar Year in 1932/33. Finally, the article describes the important investigations made by Knud Lassen during, among others, the International Geophysical Year 1957/58 and during the International Quiet Sun Year (IQSY) in 1964/65. With his leadership the auroral and geomagnetic research at DMI reached a high international

  17. Continuous auroral activity related to high speed streams with interplaneraty ALFV&N wave trains

    NASA Technical Reports Server (NTRS)

    Guarnieri, Fernando L.; Tsurutani, Bruce T.; Gonzalez, Walter D.; Kamide, Yosuke; Zhou, Xiaoyan

    2004-01-01

    We discuss a type of intense magnetospheric/auroral activity that is not always substorms: High-Intensity, Long-Duration, Continuous AE Activity (HILDCAA) events, which occur during high speed solar wind streams. The high speed streams contain large-amplitude, nonlinear Alfvtn waves. Analyses of POLAR UV images, demonstrate that the AE increases/AL decreases in HILDCAAs are not always substorm expansion phases (although some substorms may occur). The associated auroral W energy deposition is throughout a continuous (360') auroral oval. During some image intervals, the dayside aurora is the most remarkable feature. Our hypothesis is that solar wind energy transfer from the solar wind to the magnetosphere/ionosphere is primarily directly driven due to the finite wavelength Alfv6n waves and the rapid dBz/dt variability.

  18. Auroral mechanisms and morphology

    NASA Technical Reports Server (NTRS)

    Swift, D. W.

    1979-01-01

    The present review is concerned with observations, analysis of observations and theoretical work as related to the understanding of the aurora. The ground-based observations reviewed include (1) auroral imagery, both by television and all-sky camera; (2) gross magnetic variations indicative of ionospheric currents; (3) VLF hiss observations; and (4) effects of high-energy electron impact measured through cosmic radio noise absorption and by observations of bremsstrahlung X-ray from balloons. Spectroscopic observations, observation of micropulsation activity and auroral radar observations are not included, since they seem to provide less direct diagnostic information on the basic auroral mechanism. Incoherent scatter radar observations are utilized to the extent they provide information on ionospheric currents and electric fields. Satellite observations are included to the extent they provide information on the aurora or useful clues to auroral mechanisms. Barium injection experiments in the auroral zone are also considered.

  19. Engaging the Athabascan Native American students of Venetie, Alaska in the auroral research occurring over their village

    NASA Astrophysics Data System (ADS)

    Michell, R. G.; Powell, D.; Samara, M.; Jahn, J.; Pfeifer, M.; Ibarra, S.; Hampton, D. L.

    2012-12-01

    During February 2012, an optical auroral obversing campaign was conducted from the remote village of Venetie, located in North-central Alaska. The approximately 200 people in the village of are mostly Gwich'in Athabaskan. Venetie is in a unique location in that it is one of the only villages that has sounding rockets launched directly over it. While there for the research campaign of approximately one week, I spent several days meeting with and talking to the students about the auroral research that occurs literaly over their village. The John Fredson School in Venetie is a K-12 school and I was able to talk with all of the classes. They were very receptive and interested in science, but have very limited connectivity with the rest of the world, even with a slow internet connection at the school. Their perspective about the aurora is completely different, for them, the aurora is a nearly everyday experience in the winter and therefore they do not think much of it, much like students in the lower 48 would think of clouds. Using the internet, we were able to connect the 4th and 5th grade students in Venetie (through Skype) with a group of 4th and 5th grade students at Sunshine Cottage School for Deaf Children in San Antonio, TX. This was very successful on both ends and resulted in many ideas for future activities. We will discuss the experiences from this trip and the lessons learned for conducting K-12 outreach in such remote schools.; Dr. Michell presenting to the students in Venetie, AK. ; Tribal office building in Venetie, AK, with the aurora overhead.

  20. East-west type precursor activity prior to the auroral onset: Ground-based and THEMIS observations

    NASA Astrophysics Data System (ADS)

    Golovchanskaya, I. V.; Kornilov, I. A.; Kornilova, T. A.

    2015-02-01

    Using ground-based optical observations, we study an auroral breakup event, focusing on the wave-like signatures of the east-west (E-W) type auroral activities which appear before breakup. By conjunction with the Time History of Events and Macroscale Interactions during Substorms (THEMIS) P2 and P5 measurements, it is shown that the underlying wave mode can be identified as the ballooning mode. Considering the similarity of the wave-like characteristics derived from ground-based auroral and THEMIS spacecraft observations, we argue that the E-W activities under study may be related to ballooning waves propagating in the plasma sheet. The implications for mechanisms of substorm triggering are discussed.

  1. Investigations of the auroral luminosity distribution and the dynamics of discrete auroral forms in a historical retrospective

    NASA Astrophysics Data System (ADS)

    Feldstein, Y. I.; Vorobjev, V. G.; Zverev, V. L.; Förster, M.

    2014-05-01

    Research results about planetary-scale auroral distributions are presented in a historical retrospective, beginning with the first "maps of isochasms" - lines of equal visibility of auroras in the firmament (Fig. 2) - up to "isoaurora maps" - lines of equal occurrence frequency of auroras in the zenith (Fig. 4). The exploration of auroras in Russia from Lomonosov in the 18th century (Fig. 1) until the start of the International Geophysical Year (IGY) in 1957 is shortly summed up. A generalised pattern of discrete auroral forms along the auroral oval during geomagnetically very quiet intervals is presented in Fig. 5. The changes of discrete auroral forms versus local time exhibit a fixed pattern with respect to the sun. The auroral forms comprise rays near noon, homogeneous arcs during the evening, and rayed arcs and bands during the night and in the morning. This fixed auroral pattern is unsettled during disturbances, which occur sometimes even during very quiet intervals. The azimuths of extended auroral forms vary with local time. Such variations in the orientation of extended forms above stations in the auroral zone have been used by various investigators to determine the position of the auroral oval (Fig. 9). Auroral luminosity of the daytime and nighttime sectors differ owing to different luminosity forms, directions of motion of the discrete forms, the height of the luminescent layers, and the spectral composition (predominant red emissions during daytime and green emissions during the night). Schemes that summarise principal peculiarities of daytime luminosity, its structure in MLT (magnetic local time) and MLat (magnetic latitude) coordinates, and the spectral composition of the luminosity are presented in Figs. 15 and 19. We discuss in detail the daytime sector dynamics of individual discrete forms for both quiet conditions and auroral substorms. The most important auroral changes during substorms occur in the nighttime sector. We present the evolution of

  2. Spectral analysis of auroral geomagnetic activity during various solar cycles between 1960 and 2014

    NASA Astrophysics Data System (ADS)

    Kotzé, Pieter Benjamin

    2016-12-01

    In this paper we use wavelets and Lomb-Scargle spectral analysis techniques to investigate the changing pattern of the different harmonics of the 27-day solar rotation period of the AE (auroral electrojet) index during various phases of different solar cycles between 1960 and 2014. Previous investigations have revealed that the solar minimum of cycles 23-24 exhibited strong 13.5- and 9.0-day recurrence in geomagnetic data in comparison to the usual dominant 27.0-day synodic solar rotation period. Daily mean AE indices are utilized to show how several harmonics of the 27-day recurrent period change during every solar cycle subject to a 95 % confidence rule by performing a wavelet analysis of each individual year's AE indices. Results show that particularly during the solar minimum of 23-24 during 2008 the 27-day period is no longer detectable above the 95 % confidence level. During this interval geomagnetic activity is now dominated by the second (13.5-day) and third (9.0-day) harmonics. A Pearson correlation analysis between AE and various spherical harmonic coefficients describing the solar magnetic field during each Carrington rotation period confirms that the solar dynamo has been dominated by an unusual combination of sectorial harmonic structure during 23-24, which can be responsible for the observed anomalously low solar activity. These findings clearly show that, during the unusual low-activity interval of 2008, auroral geomagnetic activity was predominantly driven by high-speed solar wind streams originating from multiple low-latitude coronal holes distributed at regular solar longitude intervals.

  3. Auroral activity associated with Kelvin-Helmholtz instability at the inner edge of the low-latitude boundary layer

    NASA Technical Reports Server (NTRS)

    Farrugia, C. J.; Sandholt, P. E.; Burlaga, L. F.

    1994-01-01

    Auroral activity occurred in the late afternoon sector (approx. 16 MLT) in the northern hemisphere during the passage at Earth of an interplanetary magnetic cloud on January 14, 1988. The auroral activity consisted of a very dynamic display which was preceded and followed by quiet auroral displays. During the quiet displays, discrete rayed arcs aligned along the geomagnetic L shells were observed. In the active stage, rapidly evolving spiral forms centered on magnetic zenith were evident. The activity persisted for many minutes and was characterized by the absence of directed motion. They were strongly suggestive of intense filaments of upward field-aligned currents embedded in the large-scale region 1 current system. Distortions of the flux ropes as they connect from the equatorial magnetosphere to the ionosphere were witnessed. We assess as possible generating mechanisms three nonlocal sources known to be associated with field-aligned currents. Of these, partial compressions of the magnetosphere due to variations of solar wind dynamic pressure seem an unlikely source. The possibility that the auroral forms are due to reconnection is investigated but is excluded because the active aurora were observed on the closed field line region just equatorward of the convection reversal boundary. To support this conclusion further, we apply recent results on the mapping of ionospheric regions to the equatorial plane based on the Tsyganenko 1989 model (Kaufmann et al., 1993). We find that for comparable magnetic activity the aurora map to the equatorial plane at X(sub GSM) = approx. 3 R(sub E) and approx. 2 R(sub E) inward of the magnetopause, that is, the inner edge of the boundary layer close to dusk. Since the auroral forms are manifestly associated with magnetic field shear, a vortical motion at the equatorial end of the flux rope is indicated, making the Kelvin-Helmholtz instability acting at the inner edge of the low-latitude boundary layer the most probable generating

  4. Responses of the Equatorial Ionosphere to High Intensity Long Duration Continuous Auroral Activity

    NASA Astrophysics Data System (ADS)

    Sobral, J. H. A.; Abdu, M. A.; Gonzalez, W. D.; Gonzalez, A. C.; Tsurutani, B.; Daniela, D. C.; Arruda, C. S.

    This work focus the responses of the equatorial ionosphere over South America to intense substorms and, on the other hand, in the absence of magnetic storms. The substorms here concerned are related to what is known as High Intensity Long Duration Continuous Auroral Activity HILDCAA's. The analysis of these responses are carried out by means of ground-based ionosonde data from Fortaleza (3° 53'S 38° 25'W dip 2.7S for the epoch 1978-1979) and Cachoeira Paulista (22° 41'S , 45° 00W, dip 25.6S for 1978-1979)and ISEE-3 (Interplanetary Sun-Earth Explorer) satellite data during the 1978-1979 time frame. The substorm disturbed days are compared with the averages of quiet days. The ionospheric height variations are analyzed in the light of satellite data and intercomparisons of the two stations.

  5. Multipoint observations of nightside auroral activity: the Cascades2 sounding rocket mission

    NASA Astrophysics Data System (ADS)

    Lynch, K. A.; Mella, M. R.; Kintner, P. M.; Lundberg, E. T.; Lessard, M.; Jones, S.; Stenbaek-Nielsen, H. C.; Hampton, D. L.; Ivchenko, N. V.; Dahlgren, H.

    2009-12-01

    Cascades2 was launched from Poker Flat Alaska on 20 Mar 2009 at 11:04 UT (roughly 30 minutes premidnight magnetic local time.) The 12 minute 43 second flight reached an apogee of 564 km over the northern coast of Alaska at 11:11:11 UT, and entered the polar cap at 11:14:40 UT before atmospheric reentry at 11:16:42 UT. The experiment array included a 5-payload suite of in situ instrumentation, ground cameras of various fields of view at three different points under the trajectory, various ground magnetometers, the PFISR radar at the launch site, and the THEMIS spacecraft in the magnetotail. The array design was chosen to address questions about (1) shears in ionospheric electric fields and their ability to drive waves; (2) proper motion of auroral structures with respect to the ambient ionosphere; and (3) quantifying parameters of dispersive Alfven wave phenomena and their effects on auroral fluxtubes. The successful flight was due to the sustained and dedicated effort of the many and varied members of our team. The Cascades2 trajectory passed through several parts of a poleward boundary intensification event, with both inverted-V type aurora and sustained Alfvenic activity seen. Other presentations will detail the ground camera, onboard DC electric fields, and onboard multipoint electron data. In this presentation we show onboard magnetometer results of current signatures both compressional and transverse. Also we present ion data showing the complex motion of low and medium energy ions in these poleward boundary events; ions are seen to be both moving upward along the field line, and then precipitating back down at higher energies with dispersion signatures.

  6. Experimental studies of auroral arc generators

    SciTech Connect

    Suszcynsky, D.M.; Borovsky, J.E.; Thomsen, M.F.

    1997-08-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). An all-sky video camera system was deployed in Eagle, Alaska at the foot of the magnetic field line that threads geosynchronous satellite 1989-046 as part of a campaign to study correlations of ground-based auroral activity with satellite-based plasma and energetic particle measurements. The overall intent of the project was to study magnetosphere-ionosphere coupling as it relates to the aurora, and, in particular, to look for signatures that may help to identify various auroral generator mechanism(s). During this study, our efforts were primarily directed towards identifying the generator mechanism(s) for pulsating aurora. Our data, though not conclusive, are found to support theories that propose a cyclotron resonance mechanism for the generation of auroral pulsations.

  7. Substorm evolution of auroral structures

    NASA Astrophysics Data System (ADS)

    Partamies, N.; Juusola, L.; Whiter, D.; Kauristie, K.

    2015-07-01

    Auroral arcs are often associated with magnetically quiet time and substorm growth phases. We have studied the evolution of auroral structures during global and local magnetic activity to investigate the occurrence rate of auroral arcs during different levels of magnetic activity. The ground-magnetic and auroral conditions are described by the magnetometer and auroral camera data from five Magnetometers — Ionospheric radars — All-sky cameras Large Experiment stations in Finnish and Swedish Lapland. We identified substorm growth, expansion, and recovery phases from the local electrojet index (IL) in 1996-2007 and analyzed the auroral structures during the different phases. Auroral structures were also analyzed during different global magnetic activity levels, as described by the planetary Kp index. The distribution of auroral structures for all substorm phases and Kp levels is of similar shape. About one third of all detected structures are auroral arcs. This suggests that auroral arcs occur in all conditions as the main element of the aurora. The most arc-dominated substorm phases occur in the premidnight sector, while the least arc-dominated substorm phases take place in the dawn sector. Arc event lifetimes and expectation times calculated for different substorm phases show that the longest arc-dominated periods are found during growth phases, while the longest arc waiting times occur during expansion phases. Most of the arc events end when arcs evolve to more complex structures. This is true for all substorm phases. Based on the number of images of auroral arcs and the durations of substorm phases, we conclude that a randomly selected auroral arc most likely belongs to a substorm expansion phase. A small time delay, of the order of a minute, is observed between the magnetic signature of the substorm onset (i.e., the beginning of the negative bay) and the auroral breakup (i.e., the growth phase arc changing into a dynamic display). The magnetic onset was

  8. Auroral research at the Tromsø Northern Lights Observatory: the Harang directorship, 1928-1946

    NASA Astrophysics Data System (ADS)

    Egeland, Alv; Burke, William J.

    2016-03-01

    The Northern Lights Observatory in Tromsø began as Professor Lars Vegard's dream for a permanent facility in northern Norway, dedicated to the continuous study of auroral phenomenology and dynamics. Fortunately, not only was Vegard an internationally recognized spectroscopist, he was a great salesman and persuaded the Rockefeller Foundation that such an observatory represented an important long-term investment. A shrewd judge of talent, Vegard recognized the scientific and managerial skills of Leiv Harang, a recent graduate from the University of Oslo, and recommended that he become the observatory's first director. In 1929, subsequent to receiving the Rockefeller Foundation grant, the University of Oslo established a low temperature laboratory to support Vegard's spectroscopic investigations. This paper follows the scientific accomplishments of observatory personnel during the 18 years of Harang's directorship. These include: identifying the chemical sources of auroral emissions, discovering the Vegard-Kaplan bands, quantifying height distributions of different auroral forms, interpreting patterns of magnetic field variations, remotely probing auroral electron distribution profiles in the polar ionosphere, and monitoring the evolving states of the ozone layer. The Rockefeller Foundation judges got it right: the Tromsø Nordlysobservatoriet was, and for decades remained, an outstanding scientific investment.

  9. Auroral particles

    NASA Astrophysics Data System (ADS)

    Evans, David S.

    1987-06-01

    The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries.

  10. Auroral particles

    NASA Technical Reports Server (NTRS)

    Evans, David S.

    1987-01-01

    The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries.

  11. Rocket Auroral Correlator Experiment

    NASA Technical Reports Server (NTRS)

    LaBelle, James

    2003-01-01

    Dartmouth College provided a multi-channel high- and low- frequency wave receivers, including active sensors on deployable booms, to the Rocket Auroral Correlator Experiment launched from Poker Flat, Alaska, in January 2002. College also performed preliminary analysis of the data. Details are outlined in chronological order.

  12. The application of soft X-ray imaging techniques to auroral research

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The feasibility of building and operating a grazing incidence X-ray telescope for auroral zone studies from the Polar Plasma Laboratory (PPL) is discussed. A detailed structural analysis of the preferred design, an array of seven nested Wolter mirrors, is presented. An engineering evaluation of the requirements for the instrumental configuration, power, weight and telemetry is included. The problems of radiation hardening and thermal control are discussed. The resulting strawman instrument is presented.

  13. The Auroral Spatial Structures Probe: magnetic and electric field measurements during an active aurora at fine spatial and temporal scales

    NASA Astrophysics Data System (ADS)

    Martineau, R. J.; Pratt, J.; Swenson, C.

    2015-12-01

    The Auroral Spatial Structures Probe was a rocket campaign that launched from Poker Flat on January 28, 2015 at 10:41:01 UTC to make multi-point vector observations of the magnetic and electric fields during an active aurora. With 6 instrumented payloads deployed from the rocket in addition to the main payload, each payload making simultaneous measurements of the magnetic and electric fields, the goals of this mission are to resolve the temporal-spatial ambiguity concerning the structures of the electric and magnetic fields during an active auroral event. The vector nature of these measurements requires an accurate knowledge of attitude throughout the flight. Each payload was equipped with gyroscopes to obtain a post-processed attitude solution after the flight. While the main payload's inertial sensors functioned well, the spin axis gyroscope on the subpayloads saturated due to a design flaw. To obtain the attitude and render the vector measurements useful, a least-squares based approach to estimate the attitude history of the payloads was devised using the magnetic and electric field measurements. Once the attitude solution was applied the temporal structures seen in the magnetic and electric fields while flying through the auroral arc are strongly correlated between payloads. We present the new attitude history estimation approach and discuss its strengths and weaknesses compared to traditional attitude methods. We also present preliminary findings from the magnetic and electric field instruments.The Auroral Spatial Structures Probe was a rocket campaign that launched from Poker Flat on January 28, 2015 at 10:41:01 UTC to make multi-point vector observations of the magnetic and electric fields during an active aurora. With 6 instrumented payloads deployed from the rocket in addition to the main payload, each payload making simultaneous measurements of the magnetic and electric fields, the goals of this mission are to resolve the temporal-spatial ambiguity

  14. Energetic auroral and polar ion outflow at DE 1 altitudes Magnitude, composition, magnetic activity dependence, and long-term variations

    NASA Technical Reports Server (NTRS)

    Yau, A. W.; Lenchyshyn, L.; Shelley, E. G.; Peterson, W. K.

    1985-01-01

    Data acquired from the Dynamics Explorer I Energetic Ion Composition Spectrometer in the period from September 1981 to May 1984 are used to determine the magnitude of the terrestrial ion outflow in the 0.01-17 keV/el range. The data are also employed to investigate the mass composition and topology (local time and invariant latitude distributions) of the ion outflow, as well as the outflow's magnetic activity dependence and long-term variation. The relative importance of auroral versus polar cap upflowing ions as a source of energetic plasma for various parts of the magnetosphere is examined.

  15. Quantifying the auroral response from measured source populations of electrons and electromagnetic wave activity

    NASA Astrophysics Data System (ADS)

    Samara, M.; Michell, R.; Grubbs, G. A., II; Davidson, R. K.; Khazanov, G. V.; Glocer, A.; Hampton, D.

    2015-12-01

    A case study is presented, where a quantitative connection is made between the measured auroral intensities and the source populations of electromagnetic waves and trapped electrons measured by THEMIS. We combine a theoretical model and high-resolution multi-spectral ground based imaging of the aurora at the THEMIS footpoint in order to interpret these data in the context of the coupled magnetosphere-ionosphere system. The THEMIS wave and particle measurements form the inputs into the Khazanov, et al., 2014 model that uses a Boltzman-Landau kinetic equation, uniformly describing the entire electron distribution function, which includes the affiliated production of secondary electrons (E < 600 eV) and their associated ionosphere-magnetosphere coupling processes. The model output will in turn be used to determine the expected auroral intensities (in Rayleighs) when considering only the primary precipitating electrons and also when both the primary and mirroring secondary electrons are included. These predicted auroral intensities will be compared to measured ones from several ground-based imagers at Poker Flat, AK, where we have high-resolution multiple emission line (557.7 nm and 427.8 nm) data at a 3.3 Hz frame rate.

  16. High Frequency Active Auroral Research Program (HAARP) Imager

    DTIC Science & Technology

    1993-09-30

    Irving S(. I. Brookline MA 02146 AR U7,1994 30 September, 1993B Final Report 94-08551 19 August, 1991 -29 August., 1993 1iI .. ’I pII ll! 111 II ii I...91-C-0141 7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) 8. PERFORMING ORGANIZATION Keo Consultants REPORT NUMBER 27 Irving St. Brookline MA 02146

  17. Evaluating auroral processes within a magnotospheric model. Final report

    SciTech Connect

    Lyons, L.R.

    1989-01-01

    A summary of the research performed is included. Topics covered include magnetospheric model; association between discrete auroras and ion precipitation from the tail current sheet; auroral arc scale sizes and structures; polar cap size variation; low-altitude auroral boundary; auroral wave-particle interactions; thermospheric interactions; and the neutral wind flywheel.

  18. Modelling of auroral electrodynamical processes: Magnetosphere to mesosphere. Final Report

    SciTech Connect

    Chiu, Y.T.; Gorney, D.J.

    1982-01-01

    Research conducted on auroral electrodynamic coupling between the magnetosphere and ionosphere-atmosphere in support of the development of a global scale kinetic plasma theory is reviewed. Topics covered include electric potential structure in the evening sector, morning and dayside auroras, auroral plasma formation, electrodynamic coupling with the thermosphere, and auroral electron interaction with the atmosphere.

  19. On the uniqueness of linear moving-average filters for the solar wind-auroral geomagnetic activity coupling

    NASA Technical Reports Server (NTRS)

    Vassiliadis, D.; Klimas, A. J.

    1995-01-01

    The relation between the solar wind input to the magetosphere, VB(sub South), and the auroral geomagnetic index AL is modeled with two linear moving-average filtering methods: linear prediction filters and a driven harmonic oscillator in the form of an electric circuit. Although the response of the three-parameter oscillator is simpler than the filter's, the methods yield similar linear timescales and values of the prediction-observation correlation and the prediction Chi(exp 2). Further the filter responses obtained by the two methods are similar in their long-term features. In these aspects the circuit model is equivalent to linear prediction filtering. This poses the question of uniqueness and proper interpretation of detailed features of the filters such as response peaks. Finally, the variation of timescales and filter responses with the AL activity level is discussed.

  20. Dependence of the high-latitude plasma irregularities on the auroral activity indices: a case study of 17 March 2015 geomagnetic storm

    NASA Astrophysics Data System (ADS)

    Cherniak, Iurii; Zakharenkova, Irina

    2015-09-01

    The magnetosphere substorm plays a crucial role in the solar wind energy dissipation into the ionosphere. We report on the intensity of the high-latitude ionospheric irregularities during one of the largest storms of the current solar cycle—the St. Patrick's Day storm of 17 March 2015. The database of more than 2500 ground-based Global Positioning System (GPS) receivers was used to estimate the irregularities occurrence and dynamics over the auroral region of the Northern Hemisphere. We analyze the dependence of the GPS-detected ionospheric irregularities on the auroral activity. The development and intensity of the high-latitude irregularities during this geomagnetic storm reveal a high correlation with the auroral hemispheric power and auroral electrojet indices (0.84 and 0.79, respectively). Besides the ionospheric irregularities caused by particle precipitation inside the polar cap region, evidences of other irregularities related to the storm enhanced density (SED), formed at mid-latitudes and its further transportation in the form of tongue of ionization (TOI) towards and across the polar cap, are presented. We highlight the importance accounting contribution of ionospheric irregularities not directly related with particle precipitation in overall irregularities distribution and intensity.

  1. Using a tag team of undergraduate researchers to construct an empirical model of auroral Poynting flux, from satellite data

    NASA Astrophysics Data System (ADS)

    Cosgrove, R. B.; Bahcivan, H.; Klein, A.; Ortega, J.; Alhassan, M.; Xu, Y.; Chen, S.; Van Welie, M.; Rehberger, J.; Musielak, S.; Cahill, N.

    2012-12-01

    Empirical models of the incident Poynting flux and particle kinetic energy flux, associated with auroral processes, have been constructed using data from the FAST satellite. The models were constructed over a three-year period by a tag-team of three groups of undergraduate researchers from Worcester Polytechnic Institute (WPI), working under the supervision of researchers at SRI International, a nonprofit research institute. Each group spent one academic quarter in residence at SRI, in fulfillment of WPI's Major Qualifying Project (MQP), required for graduation from the Department of Electrical and Computer Engineering. The MQP requires a written group report, which was used to transition from one group to the next. The student's research involved accessing and processing a data set of 20,000 satellite orbits, replete with flaws associated with instrument failures, which had to be removed. The data had to be transformed from the satellite reference frame into solar coordinates, projected to a reference altitude, sorted according to geophysical conditions, and etc. The group visits were chaperoned by WPI, and were jointly funded. Researchers at SRI were supported by a grant from the National Science Foundation, which was tailored to accommodate the undergraduate tag-team approach. The NSF grant extended one year beyond the student visits, with increased funding in the final year, permitting the researchers at SRI to exercise quality control, and to produce publications. It is expected that the empirical models will be used as inputs to large-scale general circulation models (GCMs), to specify the atmospheric heating rate at high altitudes.; Poynting Flux with northward IMF ; Poynting flux with southward IMF

  2. Auroral plasma waves

    NASA Technical Reports Server (NTRS)

    Gurnett, Donald A.

    1989-01-01

    A review is given of auroral plasma wave phenomena, starting with the earliest ground-based observations and ending with the most recent satellite observations. Two types of waves are considered, electromagnetic and electrostatic. Electromagnetic waves include auroral kilometric radiation, auroral hiss, ELF noise bands, and low-frequency electric and magnetic noise. Electrostatic waves include upper hybrid resonance emissions, electron cyclotron waves, lower hybrid waves, ion cyclotron waves and broadband electrostatic noise. In each case, a brief overview is given describing the observations, the origin of the instability, and the role of the waves in the physics of the auroral acceleration region.

  3. The enigma of auroral spirals

    NASA Astrophysics Data System (ADS)

    Haerendel, G.

    One of the most spectacular forms that the aurora borealis can assume is the large-scale spiral Spirals are dominantly observed along the poleward boundary of the auroral oval during active periods Two concepts have been pursued in explaining their origin and in particular the counterclockwise sense of rotation of the luminous structures when viewed along the magnetic field direction An essentially magnetostatic theory following Hallinan 1976 attributes the spiral pattern to the twisting of field-lines caused by a centrally located upward field-aligned current According to Oguti 1981 and followers a clockwise rotation of the plasma flow produces the anticlockwise structure There are observations seemingly confirming or contradicting either theory In this paper it is argued that both concepts are insufficient in that only parts of the underlying physics are considered Besides field-aligned currents and plasma flow one has to take into at least two further aspects The ionospheric conductivity modified by particle precipitation has an impact on the magnetospheric plasma dynamics Furthermore auroral arcs are not fixed entities subject to distortions by plasma flows or twisted field-lines but sites of transient releases of energy We suggest that auroral spirals are ports of entry or exit of plasma into or out of the auroral oval This way it can be understood why a clockwise plasma flow can create an anticlockwise luminous pattern

  4. Characterization and diagnostic methods for geomagnetic auroral infrasound waves

    NASA Astrophysics Data System (ADS)

    Oldham, Justin J.

    Infrasonic perturbations resulting from auroral activity have been observed since the 1950's. In the last decade advances in infrasonic microphone sensitivity, high latitude sensor coverage, time series analysis methods and computational efficiency have elucidated new types of auroral infrasound. Persistent periods of infrasonic activity associated with geomagnetic sub-storms have been termed geomagnetic auroral infrasound waves [GAIW]. We consider 63 GAIW events recorded by the Fairbanks, AK infrasonic array I53US ranging from 2003 to 2014 and encompassing a complete solar cycle. We make observations of the acoustic features of these events alongside magnetometer, riometer, and all-sky camera data in an effort to quantify the ionospheric conditions suitable for infrasound generation. We find that, on average, the generation mechanism for GAIW is confined to a region centered about ~60 0 longitude east of the anti-Sun-Earth line and at ~770 North latitude. We note furthermore that in all cases considered wherein imaging riometer data are available, that dynamic regions of heightened ionospheric conductivity periodically cross the overhead zenith. Consistent features in concurrent magnetometer conditions are also noted, with irregular oscillations in the horizontal component of the field ubiquitous in all cases. In an effort to produce ionosphere based infrasound free from the clutter and unknowns typical of geophysical observations, an experiment was undertaken at the High Frequency Active Auroral Research Program [HAARP] facility in 2012. Infrasonic signals appearing to originate from a source region overhead were observed briefly on 9 August 2012. The signals were observed during a period when an electrojet current was presumed to have passed overhead and while the facilities radio transmitter was periodically heating the lower ionosphere. Our results suggest dynamic auroral electrojet currents as primary sources of much of the observed infrasound, with

  5. Vlasov simulations of auroral processes

    NASA Astrophysics Data System (ADS)

    Gunell, H.; De Keyser, J. M.; Mann, I.

    2013-12-01

    In the auroral zone, electric fields that are parallel to the magnetic field are known to exist. These fields contribute to the acceleration of the electrons that cause the auroral emissions. Thus, parallel electric fields form an integral part of the auroral current circuit. Transverse electric fields at high altitude result in parallel electric fields as a consequence of the closure of the field aligned currents through the conducting ionosphere. The parallel electric fields can be supported by the magnetic mirror field, by electric double layers, or both. We present Vlasov simulations of the plasma on a magnetic field line from the equatorial magnetosphere to the auroral ionosphere. In the upward current region, we find that about two thirds of the total voltage is concentrated in a stationary double layer at an altitude of about one earth radius. In the downward current region, double layers form and move upward not reaching a steady state. For equal currents in the two regions, the voltage is significantly lower in the downward than in the upward current region. Waves on electron time scales and vortices in electron phase space form on the high potential side of the double layers in the downward current region. Finally, we discuss how laboratory experiments can be used to simulate auroral acceleration and present computer simulations of a possible a laboratory configuration. This work was supported by the Belgian Science Policy Office through the Solar-Terrestrial Centre of Excellence and by PRODEX/Cluster PEA 90316. This research was conducted using the resources of the High Performance Computing Center North (HPC2N) at Umeå University in Sweden.

  6. Global scale auroral emissions on Jupiter

    NASA Technical Reports Server (NTRS)

    Trafton, L.

    1991-01-01

    Jupiter's aurora are normally confined to limited regions around the magnetic poles. Our collected spectra show that very unusual periods of global scale auroral activity occurred during September and November of 1988. During the global scale events, the H2 and H3(+) emissions remained confined to their unusual auroral zones, but strong, unidentified emissions appeared in the vicinity of the H2 quadrupole lines. This would suggest that unusual periods of widespread magnetospheric dumping occurred.

  7. Spatial distribution of auroral precipitation during storms caused by magnetic clouds

    NASA Astrophysics Data System (ADS)

    Yagodkina, O. I.; Despirak, I. V.; Vorobjev, V. G.

    2012-03-01

    The global pattern of auroral precipitation and dynamics of precipitation boundaries during three different intensity magnetic storms driven by magnetic clouds were investigated. For the aim of the research, the empirical model (http://pgia.ru/lang/en/webapps/) in which the boundary locations of the auroral precipitation depend on the geomagnetic activity expressed by the AL- and Dst indices was used. The locations of the boundaries derived from DMSP F10-F15 spacecraft observations were compared to those obtained in the model and displayed reasonable agreement. We find a significant displacement to the lower latitudes of the diffuse auroral zone (DAZ) and auroral oval precipitation (AOP) region with the increase of magnetic activity. The planetary pattern of auroral precipitation indicated different dawn-dusk widening of the DAZ and AOP region (asymmetry) during both main and recovery phases of magnetic storms. Differences in the dawn-dusk widening (i.e., asymmetry) of the DAZ and AOP zone during magnetic storms appear to be sensitive to Dst, where the DAZ widens in the morning only, while the AOP widens in the evening under all Dst intensities, and widens significantly in the morning also for Dst<-100 nT. The average energy of precipitating electrons in both MLT sectors and both zones was estimated and compared with DMSP spacecraft data.

  8. Active wave experiment on the slow Z mode using a separated transmitter and receiver in the auroral ionosphere

    NASA Astrophysics Data System (ADS)

    James, G.

    2003-04-01

    Slow Z-mode waves were observed during the OEDIPUS-C (OC) mother-son rocket experiment. Waves were transmitted from an active double-V dipole on one subpayload and received at a distance of about 1200 m on a similar dipole connected to a synchronized receiver. Bistatic propagation was obtained at frequencies f in max{fc,fp}active dipole has been replaced by a model involving incoherent radiation from sounder-accelerated electrons (SAE). Previous publications show that the OC transmitting dipole produces strong SAE at energies from 10 eV up to 10 keV when the transmitting frequency sweeps through the above mentioned frequency range. The transmitting dipole pushes SAE helically downward in the general direction of the receiver. At every instant, each SAE particle creates radiation that obeys the resonance condition f-mfc = (nf/c)cos(theta)Vcos(alpha), where m is a signed integer, n the Z-mode refractive index, theta the angle between the direction of propagation of the radiation and B, V the electron speed and alpha its pitch angle. Using the reported SAE energies, it is found that time delays like those observed can be explained with Z-mode n and theta values, for m = 0, 1 or 2. The resonance condition and dispersion relation together require theta values near the upper-oblique resonance cone. The Z mode is

  9. Research Activities.

    ERIC Educational Resources Information Center

    Santa Fe Community Coll., Gainesville, FL.

    The five parts of this report are: research on instruction; faculty dissertations; inter-institutional research; in-college research; and college-endorsed research. The first covers experiments in teaching French, practical nursing, English, math, and chemistry, and in giving examinations. Faculty dissertations include studies of post-graduate…

  10. Auroral activities observed by SNPP VIIRS day/night band during a long period geomagnetic storm event on April 29-30, 2014

    NASA Astrophysics Data System (ADS)

    Shao, Xi; Cao, Changyong; Liu, Tung-chang; Zhang, Bin; Wang, Wenhui; Fung, Shing F.

    2015-10-01

    The Day/Night Band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi-NPP represents a major advancement in night time imaging capabilities. The DNB senses radiance that can span 7 orders of magnitude in one panchromatic (0.5-0.9 μm) reflective solar band and provides imagery of clouds and other Earth features over illumination levels ranging from full sunlight to quarter moon. When the satellite passes through the day-night terminator, the DNB sensor is affected by stray light due to solar illumination on the instrument. With the implementation of stray light correction, stray light-corrected DNB images enable the observation of aurora occurred in the high latitude regions during geomagnetic storms. In this paper, DNB observations of auroral activities are analyzed during a long period (> 20 hours) of geomagnetic storm event occurred on Apr. 29-30, 2014. The storm event has the Bz component of interplanetary magnetic field (IMF) pointing southward for more than 20 hours. During this event, the geomagnetic storm index Dst reached -67 nT and the geomagnetic auroral electrojet (AE) index increased and reached as high as 1200 nT with large amplitude fluctuations. The event occurred during new moon period and DNB observation has minimum moon light contamination. During this event, auroras are observed by DNB for each orbital pass on the night side (~local time 1:30am) in the southern hemisphere. DNB radiance data are processed to identify regions of aurora during each orbital pass. The evolution of aurora is characterized with time series of the poleward and equatorward boundary of aurora, area, peak radiance and total light emission of the aurora in DNB observation. These characteristic parameters are correlated with solar wind and geomagnetic index parameters. It is found that the evolution of total area-integrated radiance of auroral region over the southern hemisphere correlated well with the ground geomagnetic AE index with correlation

  11. Fast-moving diffuse auroral patches: A new aspect of daytime Pc3 auroral pulsations

    NASA Astrophysics Data System (ADS)

    Motoba, Tetsuo; Ebihara, Yusuke; Kadokura, Akira; Engebretson, Mark J.; Lessard, Marc R.; Weatherwax, Allan T.; Gerrard, Andrew J.

    2017-02-01

    Auroral pulsations are a convenient diagnostic of wave-particle interactions in the magnetosphere. A case study of a daytime Pc3 (22-100 mHz) auroral pulsation event, measured with a 2 Hz sampling all-sky camera at South Pole Station (74.4°S magnetic latitude) on 17 May 2012, is presented. The daytime Pc3 auroral pulsations were most active in a closed field line region where the aurora was dominated by diffuse green-line emissions and within ±2 h of magnetic local noon. Usually, but not always, the corresponding periodic variations were recorded with a colocated search coil magnetometer. Of particular interest is the two-dimensional auroral signature, indicating that the temporal luminosity variations at a given point were due to repeated formation and horizontal motion of faint, nonpulsating auroral patches with scale sizes of 100 km. The individual patches propagated equatorward with speeds of 15 km s-1 up to 20-25 km s-1 one after another along the magnetic meridian through local magnetic zenith. These properties differ considerably from typical pulsating aurorae, being periodic on-off luminosity variations in a particular auroral patch and drifting in accordance with the convection electric field in the magnetosphere. We speculate that such repetitive patterns of the fast-moving auroral patches, being another aspect of the daytime Pc3 auroral pulsations, may be a visible manifestation of compressional Pc3 waves which propagate earthward and cause modulation of precipitating keV electron fluxes in the dayside outer magnetosphere.

  12. Auroral Spatial Structures Probe Sub-Orbital Mission Preliminary Results

    NASA Astrophysics Data System (ADS)

    Pratt, J.; Swenson, C.; Martineau, R. J.; Fish, C. S.; Conde, M.; Hampton, D.; Crowley, G.

    2015-12-01

    The NASA Auroral Spatial Structures Probe, 49.002, was launched January 28, 2015 from the Poker Flat Research Range into active aurora over the northern coast of Alaska. The primary objective of this mission was to determine the contribution of small spatial and temporal scale fluctuations of the electric fields to the larger-scale energy deposition processes associated with the aurora. The Auroral Spatial Structures Probe Sub-Orbital Mission consisted of a formation of 7 spacecraft (a main payload with 6 deployable sub-payloads) designed for multiple temporally spaced co-located measurements of electric and magnetic fields in the earth's ionosphere. The mission was able to make observations at a short time scale and small spatial scale convergence that is unobservable by either satellite or ground-based observations. The payloads included magnetometers, electric field double probes, and Langmuir probes as well as a sweeping impedance probe on the main payload. We present here preliminary results from the measurements taken that hint at the underlying spatial structure of the currents and energy deposition in the aurora. The Poynting flux derived from the observations is shown and implications are discussed in terms of the contribution of small spatial scale, rapid temporal scale fluctuations in the currents that deposit energy in the auroral region. Funding provided by NASA Grants NNX11AE23G and NNX13AN20A.

  13. Revisiting geomagnetic activity at auroral latitudes: No need for regular quiet curve removal for geomagnetic activity indices based on hourly data

    NASA Astrophysics Data System (ADS)

    Martini, Daniel; Argese, Chiara; Di Loreto, Massimo; Mursula, Kalevi

    2016-07-01

    The main objective of our study is to determine if the regular quiet daily curve (QDC) subtraction is a necessary procedure in quantifying the irregular geomagnetic variations at auroral latitudes. We define the hourly ΔH index, the absolute hour-to-hour deviation in nanotesla of the hourly geomagnetic horizontal component, which assigns each sample to sample deviation as geomagnetic activity without separating the "regular" and "irregular" parts of the daily magnetic field evolution. We demonstrate that the hourly gradient of the regular Sq variation is very small with respect to the irregular part, and a bulk of the nominal daily variation is actually part of the variation driven by solar wind and interplanetary magnetic field and traditionally classified as irregular. Therefore, attempts to subtract QDC can lead to a larger error, often caused by residual deviations between the used different mathematical and methodological tools and corresponding presumptions themselves. We show that ΔH provides the best and most consistent results at most timescales with the highest effective resolution among the studied indices. We also demonstrate that the ΔH index may equally be useful as a quick-look near-real-time index of space weather and as a long-term index derived from hourly magnetometer data for space climate studies.

  14. Observations of a gradual transition between Ps 6 activity with auroral torches and surgelike pulsations during strong geomagnetic disturbances

    NASA Technical Reports Server (NTRS)

    Steen, A.; Collis, P. N.; Evans, D.; Kremser, G.; Capelle, S.; Rees, D.; Tsurutani, B. T.

    1988-01-01

    This paper describes a long-lasting large-amplitude pulsation event, which occurred on January 10, 1983 in the ionosphere and magnetosphere and was characterized by Steen and Rees (1983). Over the 4-h period (0200-0600 UT), the characteristics of the pulsations in the ionosphere changed from being Ps 6 auroral torches toward substorms and back to Ps 6. At GEO, the corresponding characteristics were a modulation of the high-energy particle intensity and plasma dropouts. Based on the ideas presented by Rostoker and Samson (1984), an interpretation of the event is offered, according to which the pulsations are caused by the Kelvin-Helmholtz instability during an interval of strong magnetospheric convection. On the basis of this explanation, a new interpretation of the substorm time sequence is proposed.

  15. Magnetospheric and auroral plasmas - A short survey of progress

    NASA Technical Reports Server (NTRS)

    Frank, L. A.

    1975-01-01

    Important milestones in our researches of auroral and magnetospheric plasmas for the past quadrennium 1971-1975 are reviewed. Many exciting findings, including those of the polar cusp, the polar wind, the explosive disruptions of the magnetotail, the interactions of hot plasmas with the plasmapause, the auroral field-aligned currents, and the striking inverted V electron precipitation events, were reported during this period. Solutions to major questions concerning the origins and acceleration of these plasmas appear possible in the near future. A comprehensive bibliography of current research is appended to this brief survey of auroral and magnetospheric plasmas.

  16. Upper Atmospheric Effects of the HF Active Auroral Research Program Ionospheric Research Instrument (HAARP IRI)

    DTIC Science & Technology

    1993-05-01

    Energetic particles generated in solar flares produce "particle events" in the upper atmosphere. The fast protons in solar proton events (SPE...Additional sources of odd nitrogen are; ionization of air by meteors and photochemical production in the thermosphere . Solar energy deposition above 100 km...Mesospheric and thermospheric NO sources [Jackman et al., 1980]. Source NO molecules/yr NO molecules/yr solar maximum solar minimum N20+O(1 D) 5.3x10 32

  17. Long-lived auroral structures and atmospheric losses through auroral flux tubes on Mars

    NASA Astrophysics Data System (ADS)

    Dubinin, E.; Fraenz, M.; Woch, J.; Barabash, S.; Lundin, R.

    2009-04-01

    The ASPERA-3 observations of electron and ion fluxes over the regions dominated by crustal magnetic fields show the existence of long-lived and active aurora-type magnetic flux tubes with a width of 20-150 km. The activity manifests itself by large electron energy fluxes (≥10-4 W/m2) and strong distortions in the upper (350-400 km) ionosphere. In some events the peaked electron energy distributions typical for Earth aurora are so pronounced that they are present in velocity distribution functions. A significant depletion of such auroral flux tubes is accompanied by the appearance of oxygen beams and a heating of the ions of ionospheric origin. Auroral activity was observed on several subsequent orbits of the Mars Express spacecraft during more than two weeks implying a stable existence of aurora on Mars. Atmospheric loss driven by energy deposition in the auroral flux tubes is estimated as ˜1023 s-1.

  18. Correlation Between Low Frequency Auroral Kilometric Radiation (AKR) and Auroral Structures

    NASA Technical Reports Server (NTRS)

    Paxamickas, Katherine A.; Green, James L.; Gallagher, Dennis L.; Boardsen, Scott; Mende, Stephen; Frey, Harald; Reinisch, Bodo W.

    2005-01-01

    Auroral Kilometric Radiation (AKR) is a radio wave emission that has long been associated with auroral activity. AKR is normally observed in the frequency range from -60 - 600 kHz. Low frequency AKR (or LF-AKR) events are characterized as a rapid extension of AKR related emissions to 30 kHz or lower in frequency for typically much less than 10 minutes. LF-AKR emissions predominantly occur within a frequency range of 20 kHz - 30 kHz, but there are LF-AKR related emissions that reach to a frequency of 5 kHz. This study correlates all instances of LF-AKR events during the first four years of observations from the IMAGE spacecraft's Radio Plasma Imager (WI) instrument with auroral observations from the wideband imaging camera (WIC) onboard IMAGE. The correlation between LF-AKR occurrence and WIC auroral observations shows that in the 295 confirmed cases of LF-AKR emissions, bifurcation of the aurora is seen in 74% of the cases. The bifurcation is seen in the dusk and midnight sectors of the auroral oval, where AKR is believed to be generated. The polarization of these LF-AKR emissions has yet to be identified. Although LF-AKR may not be the only phenomena correlated with bifurcated auroral structures, bifurcation will occur in most instances when LF-AKR is observed. The LF-AKR emissions may be an indicator of specific auroral processes sometimes occurring during storm-time conditions in which field-aligned density cavities extend a distance of perhaps 5-6 RE tailward from the Earth for a period of 10 minutes or less.

  19. Investigating the auroral electrojets using Swarm

    NASA Astrophysics Data System (ADS)

    Smith, Ashley; Macmillan, Susan; Beggan, Ciaran; Whaler, Kathy

    2016-04-01

    The auroral electrojets are large horizontal currents that flow within the ionosphere in ovals around the polar regions. They are an important aspect of space weather and their position and intensity vary with solar wind conditions and geomagnetic activity. The electrojet positions are also governed by the Earth's main magnetic field. During more active periods, the auroral electrojets typically move equatorward and become more intense. This causes a range of effects on Earth and in space, including geomagnetically induced currents in power transmission networks, disturbance to radio communications and increased drag on satellites due to expansion of the atmosphere. They are also indicative of where the aurora are visible. Monitoring of the auroral electrojets in the pre-satellite era was limited to the network of ground-based magnetic observatories, from which the traditional AE activity indices are produced. These suffer in particular from the stations' poor distribution in position and so this motivates the use of satellite-based measurements. With polar low-Earth orbit satellites carrying magnetometers, all latitudes can be sampled with excellent resolution. This poster presents an investigation using Swarm's magnetometer data to detect the electrojets as the spacecraft move above them. We compare and contrast two approaches, one which uses vector data and the other which uses scalar data (Hamilton and Macmillan 2013, Vennerstrom and Moretto, 2013). Using ideas from both approaches we determine the oval positions and intensities from Swarm and earlier satellites. The variation in latitude and intensity with solar wind conditions, geomagnetic activity and secular variation of the main field is investigated. We aim to elucidate the relative importance of these factors. Hamilton, B. and Macmillan, S., 2013. Investigation of decadal scale changes in the auroral oval positions using Magsat and CHAMP data. Poster at IAGA 12th Scientific Assembly, 2013. http

  20. Auroral ion acceleration

    NASA Astrophysics Data System (ADS)

    Shalimov, S. L.

    From the altitude of 500 km to 15 R sub E everywhere conic like distributions of H+, O+, He+ ions are moving upwards from the ionosphere along the geomagnetic field lines in the auroral zone. The distributed ions suggest the existence of ion transverse acceleration mechanisms (ITAM) acting below the observation point. The more plausible mechanisms are connected with the resonance of the type wave particle between ions and the observed EIC and LH waves and are also due to the existence of the local transverse electric fields in the ionoshere and the magnetosphere. The known ion transverse acceleration mechanisms were complemented by new results. The conical distributions of ionospheric ions at different altitudes in the auroral zone are pointed out.

  1. Theoretical and experimental studies relevant to interpretation of auroral emissions

    NASA Technical Reports Server (NTRS)

    Keffer, Charles E.

    1994-01-01

    This report describes the accomplishments of a program designed to develop the tools necessary to interpret auroral emissions measured from a space-based platform. The research was divided into two major areas. The first area was a laboratory study designed to improve our understanding of the space vehicle external environment and how it will affect the space-based measurement of auroral emissions. Facilities have been setup and measurements taken to simulate the gas phase environment around a space vehicle; the radiation environment encountered by an orbiting vehicle that passes through the Earth's radiation belts; and the thermal environment of a vehicle in Earth orbit. The second major area of study was a modeling program to develop the capability of using auroral images at various wavelengths to infer the total energy influx and characteristic energy of the incident auroral particles. An ab initio auroral calculation has been added to the extant ionospheric/thermospheric global modeling capabilities within our group. Once the addition of the code was complete, the combined model was used to compare the relative intensities and behavior of various emission sources (dayglow, aurora, etc.). Attached papers included are: 'Laboratory Facility for Simulation of Vehicle-Environment Interactions'; 'Workshop on the Induced Environment of Space Station Freedom'; 'Radiation Damage Effects in Far Ultraviolet Filters and Substrates'; 'Radiation Damage Effects in Far Ultraviolet Filters, Thin Films, and Substrates'; 'Use of FUV Auroral Emissions as Diagnostic Indicators'; and 'Determination of Ionospheric Conductivities from FUV Auroral Emissions'.

  2. Landau damping of auroral hiss

    NASA Technical Reports Server (NTRS)

    Morgan, D. D.; Gurnett, D. A.; Menietti, J. D.; Winningham, J. D.; Burch, J. L.

    1994-01-01

    Auroral hiss is observed to propagate over distances comparable to an Earth radius from its source in the auroral oval. The role of Landau damping is investigated for upward propagating auroral hiss. By using a ray tracing code and a simplified model of the distribution function, the effect of Landau damping is calculated for auroral hiss propagation through the environment around the auroral oval. Landau damping is found to be the likely mechanism for explaining some of the one-sided auroral hiss funnels observed by Dynamics Explorer 1. It is also found that Landau damping puts a lower limit on the wavelength of auroral hiss. Poleward of the auroral oval, Landau damping is found in a typical case to limit omega/k(sub parallel) to values of 3.4 x 10(exp 4) km/s or greater, corresponding to resonance energies of 3.2 keV or greater and wavelengths of 2 km or greater. For equatorward propagation, omega/k(sub parallel) is limited to values greater than 6.8 x 10(exp 4) km/s, corresponding to resonance energies greater than 13 keV and wavelengths greater than 3 km. Independent estimates based on measured ratios of the magnetic to electric field intensity also show that omega/k(sub parallel) corresponds to resonance energies greater than 1 keV and wavelengths greater than 1 km. These results lead to the difficulty that upgoing electron beams sufficiently energetic to directly generate auroral hiss of the inferred wavelength are not usually observed. A partial transmission mechanism utilizing density discontinuities oblique to the magnetic field is proposed for converting auroral hiss to wavelengths long enough to avoid damping of the wave over long distances. Numerous reflections of the wave in an upwardly flared density cavity could convert waves to significantly increased wavelengths and resonance velocities.

  3. DISCOVERY OF A DARK AURORAL OVAL ON SATURN

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The ultraviolet image was obtained by the NASA/ESA Hubble Space Telescope with the European Faint Object Camera (FOC) on June 1992. It represents the sunlight reflected by the planet in the near UV (220 nm). * The image reveals a dark oval encircling the north magnetic pole of Saturn. This auroral oval is the first ever observed for Saturn, and its darkness is unique in the solar system (L. Ben-Jaffel, V. Leers, B. Sandel, Science, Vol. 269, p. 951, August 18, 1995). The structure represents an excess of absorption of the sunlight at 220 nm by atmospheric particles that are the product of the auroral activity itself. The large tilt of the northern pole of Saturn at the time of observation, and the almost perfect symmetry of the planet's magnetic field, made this observation unique as even the far side of the dark oval across the pole is visible! * Auroral activity is usually characterized by light emitted around the poles. The dark oval observed for Saturn is a STUNNING VISUAL PROOF that transport of energy and charged particles from the magnetosphere to the atmosphere of the planet at high latitudes induces an auroral activity that not only produces auroral LIGHT but also UV-DARK material near the poles: auroral electrons are probably initiating hydrocarbon polymer formation in these regions. Credits: L. Ben Jaffel, Institut d'Astrophysique de Paris-CNRS, France, B. Sandel (Univ. of Arizona), NASA/ESA, and Science (magazine).

  4. Auroral electrodynamics I: 1. preliminary electron density profile and 2. vehicle potential changes during an active beam experiment. Memorandum report

    SciTech Connect

    Walker, D.N.; Holmes, J.C.; Szuszczewicz, E.P.

    1980-05-19

    The report presents preliminary findings obtained by a pulsed plasma probe aboard a payload launched by a Terrier-Malemute sounding rocket from the Poker Flat Research Range. Results are outlined both during passive and active (i.e., an Argon plasma gun) experiments. Modifications to the design of the pulsed probe circuitry which allow tracking of the vehicle potential are described. The vehicle potential deduced from the analog records is plotted during times of interest (gun pulsing periods). An electron density profile with gun pulsing times indicated is also provided.

  5. Auroral electron time dispersion

    SciTech Connect

    Kletzing, C.A.

    1989-01-01

    A sounding rocket flight was launched from Greenland in 1985 to study high latitude, early morning auroral physics. The payload was instrumented with electron and ion detectors, AC and DC electric field experiments, a plasma density experiment, and a magnetometer to measure the ambient field. The rocket was launched during disturbed conditions, when the polar cap was in a contracted state with visible aurora overhead. The electron data contained numerous signatures indicative of time-of-flight energy dispersion characterized by a coherent structure in which lower energy electrons arrived at the rocket after higher energy electrons. A model was constructed to explain this phenomena by the sudden application of a region of parallel electric field along a length of magnetic field line above the rocket. The model incorporates detector response and uses an altitudinal density profile based on auroral zone measurements. Three types of potential structures were tried: linear, quadratic and cubic. Of the three it was found that the cubic (electric field growing in a quadratic manner moving up the field line) produced the best fit to the data. The potential region was found to be approximately 1-2 R{sub e} in extent with the lower edge 3000-4000 km away from the rocket. The background electron temperature in the model which produced the best fit to the data was of the order of 15 eV.

  6. Ground and satellite observations of the low-latitude onsets of auroral substorm during a major magnetic storm

    NASA Astrophysics Data System (ADS)

    Ievenko, Igor; Parnikov, Stanislav; Alexeyev, Valeriy

    It is known that the first onset of auroral substorm expansion is connected with the brightness increase and breakup of the most equatorial arc. The subsequent substorm activizations can be observed in the intensification of auroral arcs at higher latitudes. As a result a formation of auroral bulge and poleward shift of a westward electrojet maximum takes place. The development of auroral bulge maps the precipitation dynamics of energetic particles during magnetospheric substorms. In this work the research results of auroral substorm during the major magnetic storm on March 20, 2001 (Dst =-150 nT) are submitted. The aurorae were registered at the Yakutsk meridian (130ºE; 200ºE, geom.) by the meridian-scanning and zenith photometers in the 630, 557.7 [OI], 427.8 (N2+) and 486.1 nm (H beta) emissions. Before the substorm onset the equatorial arc is observed at low geomagnetic latitudes of 55-57ºN (the dipole L=3.0-3.3). The zenith photometer registers an intense H beta emission in the arc (~400 R). The fast increase of the 427.8, 557.7 nm emission intensity during two equatorial arc breakups is accompanied by the decrease of H beta intensity by a factor of ~5. The aurora dynamics is compared with the measurements of precipitating flux of electrons and protons aboard DMSP F15 satellite, substorm injections at a geosynchronous orbit, variations in the solar wind and IMF and also images of the auroral oval from the IMAGE satellite. The ground and satellite observations are considered from a position of change of the magnetic field configuration during the low-latitude substorm. We assume that the sharp drop of H beta emission intensity (precipitating protons flux) during the breakups of equatorial arc may testify to a connection of its location with a proton isotropic boundary in the inner magnetosphere.

  7. Observing the magnetosphere through global auroral imaging: 1. Observables

    NASA Astrophysics Data System (ADS)

    Mende, Stephen B.

    2016-10-01

    Over the years, it has become clear that there are fundamental limitations in observing magnetospheric processes through their auroral footprints. Most electron auroras are formed in the auroral acceleration region relatively close to the Earth at altitudes (<2 RE). There are four distinct auroral types: (1) downward field-aligned current (FAC) regions where ion precipitation is dominant, (2) pitch angle diffusion aurora (or briefly "diffusion aurora") region without significant FAC, (3) upward FAC regions of precipitating electrons and monoenergetic auroral arc formations, and (4) Alfvénic auroral regions, where low-energy electrons from the ionosphere are accelerated by incoming Alfvén waves. Alfvénic auroras are the footprints of magnetospheric regions where waves are produced by dynamic events such as reconnection, substorm onset initiation, and magnetic field dipolarization. Based on the mean energy and density of the precipitating electrons, ground-based and spacecraft-based optical observations can be used to distinguish between auroras where the source is the plasma sheet (types 1, 2, and 3) and Alfvénic auroras, where the source is the ionosphere (type 4). Imaging of the Alfvénic auroral region could be used to map the dynamically active regions of the magnetosphere. The energy distribution of the most significant precipitating ions, protons, can be measured from the Doppler profile of the hydrogen emission lines. Mapping of the time dependent global energy distribution of proton precipitation would allow the observation of the associated magnetospheric boundaries.

  8. Auroral helium precipitation.

    NASA Technical Reports Server (NTRS)

    Axford, W. I.; Chivers, H. J. A.; Eberhardt, P.; Geiss, J.; Buehler, F.

    1972-01-01

    Application of the metal foil sampling technique, which has been used to measure helium, neon, and argon fluxes in the solar wind, to the problem of measuring the fluxes of these gases in the auroral primary radiation. Aluminum and platinum foils have been flown into two bright auroras and have been recovered. The foils have been analyzed for helium and neon isotopes with a mass spectrometer; so far only He4 has been detected. In the first flight the precipitating flux of He4 with particle energies above about 1 keV was approximately 1,000,000 per sq cm per sec, and the backscattered flux was smaller by about a factor of 10. In the second flight the aurora was less bright, and the He4 fluxes were lower by a factor of about 2. A rough analysis suggests that the mean energy of the incident particles was greater than 3 keV.

  9. Auroral interactions with ISSA

    NASA Technical Reports Server (NTRS)

    Purvis, Carolyn K.; Snyder, David B.; Jongeward, Gary A.

    1994-01-01

    Due to its high inclination orbit, International Space Station Alpha (ISSA) will occasionally experience surface charging by the high energy electrons of the auroral environment. This study looks at the frequency of these occurrences and recapitulates a charging model. ISSA should expect about 80 auoral encounters annually. If the plasma contactor is not run continuously, the vehicle may charge several hundred volts. Charge storage on standard space station coatings should not be a problem, but care must be taken that materials are not introduced inadvertently that cannot bleed off accumulated charge in a reasonable time. A conductivity requirement may be used to ensure surface materials do not charge to high voltages, or store charge for long periods of time.

  10. Fine structure of auroral particle acceleration

    SciTech Connect

    Lynch, K.A.

    1992-01-01

    A mass-analyzing capped hemispherical electrostatic analyzer was developed for the purpose of resolving the mass, energy, and pitch angle distributions of auroral ions. The instrument, the B-field Hemispherical Electrostatic Energy and Pitch Angle Spectrometer (BEEPS), is an extension of the HEEPS instrument, which uses a hemispherical analyzer and microchannel plates to measure the angular and energy distribution of ions. BEEPS uses a toroidal magnetic field constructed from rare-earth permanent magnets to separate ion measurements into two groups, protons and heavier ions. BEEPS was flown in February, 1991, from Poker Flat, Alaska, on the TOPAZ3 sounding rocket. This sounding rocket mission carried a full array of particle and field instrumentation to an altitude of over 1000 km. Electron data from the flight are presented and discussed in detail, and are shown in light of both ion and wave data taken during the same flight. Correspondences between the various data sets are presented. Particular note is made of the observation that ion heating seems to correspond with a field-aligned plateau in the electron distribution function below the peak electron energy. The growth rate of the n = -1 anomalous Doppler resonance of medium energy electrons with lower hybrid waves is discussed, and proposed as a mechanism for converting energy from the auroral electrons, the driver of the auroral activity, to the ion heating events.

  11. FAST/Polar Conjunction Study of Field-Aligned Auroral Acceleration and Corresponding Magnetotail Drivers

    NASA Technical Reports Server (NTRS)

    Schriver, D.; Ashour-Abdalla, M.; Strangeway, R. J.; Richard, R. L.; Klezting, C.; Dotan, Y.; Wygant, J.

    2003-01-01

    The discrete aurora results when energized electrons bombard the Earth's atmosphere at high latitudes. This paper examines the physical processes that can cause field-aligned acceleration of plasma particles in the auroral region. A data and theoretical study has been carried out to examine the acceleration mechanisms that operate in the auroral zone and to identi@ the magnetospheric drivers of these acceleration mechanisms. The observations used in the study were collected by the Fast Auroral Snapshot (FAST) and Polar satellites when the two satellites were in approximate magnetic conjunction in the auroral region. During these events FAST was in the middle of the auroral zone and Polar was above the auroral zone in the near-Earth plasma sheet. Polar data were used to determine the conditions in the magnetotail at the time field-aligned acceleration was measured by FAST in the auroral zone. For each of the magnetotail drivers identified in the data study, the physics of field-aligned acceleration in the auroral region was examined using existing theoretical efforts and/or a long-system particle in cell simulation to model the magnetically connected region between the two satellites. Results from the study indicate that there are three main drivers of auroral acceleration: (1) field-aligned currents that lead to quasistatic parallel potential drops (parallel electric fields), (2) earthward flow of high-energy plasma beams from the magnetotail into the auroral zone that lead to quasistatic parallel potential drops, and (3) large-amplitude Alfven waves that propagate into the auroral region from the magnetotail. The events examined thus far confm the previously established invariant latitudinal dependence of the drivers and show a strong dependence on magnetic activity. Alfven waves tend to occur primarily at the poleward edge of the auroral region during more magnetically active times and are correlated with intense electron precipitation. At lower latitudes away

  12. Research activities on Antarctic middle atmosphere by JARE 25th team

    NASA Technical Reports Server (NTRS)

    Hirasawa, T.; Eiwasaka, Y. AFTANAKA, M. agfujii, r.0 typ; Eiwasaka, Y. AFTANAKA, M. agfujii, r.0 typ

    1985-01-01

    The Antarctic Middle Atmosphere (AMA)-Japan research project was set about by the JARE (Japan Antarctic Research Expedition) 23rd team in 1982, and since then the JARE-24th and JARE-25th teams have been continuing reseach on the Antarctic Middle Atmosphere. Results gained by JARE-25th team members who are now working at Syowa Station (69.99 deg S, 39.35 deg E), Antarctica are presented. In their activities satellite measurements (Exos-C) and rocket soundings are used. Three rockets of the S310 type were launched at Syowa Station (Geomagnetic Latitude = 69.9 deg S) for the purpose of directly observing the electron density, ionospheric temperature, auroral patterns and luminosity in situ. Vertical profiles of electron density and auroral emission 4278A measured by three rockets are compared.

  13. Environmental Impact Statement. Volume 1. Proposed High Frequency Active Auroral Research Program

    DTIC Science & Technology

    1993-07-01

    Picea mariana Bog blueberry Vaccinium Labrador tea Ledwn groenlandicum Sedges Cyperaceae Sphagnum moss Sphagnum sp. Tamarack Larix laricina White...of 25 to 60%. A wet herbaceous vegetation association occurs in wet areas with grasses and sedges and is analogous to Cowardin et al.’s (1979...wetlands dominated by sedges and rushes. Minimal amounts of palustrine aquatic bed are present. Forested wetlands (equivalent to palustrine forested

  14. Ducted auroral kilometric radiation

    NASA Technical Reports Server (NTRS)

    Calvert, W.

    1982-01-01

    Certain discrete, intense wave signals attributed to auroral kilometric radiation (AKR) were observed with ISEE-l while it was within the plasmaspheric shadow zone for direct propagation. It is believed that wave ducting by thin depletions of the plasma density aligned with the magnetic field accounts for such signals, and that their discrete nature is caused by the satellite intercepting individual ducts. These ducts, which were also observed as coincident decreases of the upper hybrid resonance frequency, appeared to be twenty-percent depletions roughly one hundred kilometers across. The AKR, which is emitted approximately perpendicular to the magnetic field, apparently entered these ducts equatorward of the source after the waves had been refracted parallel to the duct axis. A diffuse background was also observed which is consistent with the leakage from similar ducts at lower L-values. These observations establish the existence of ducted AKR, its signature on the satellite wave spectrograms, and new evidence for depletion ducts within the plasmasphere.

  15. DMSP Auroral Charging at Solar Cycle 24 Maximum

    NASA Technical Reports Server (NTRS)

    Chandler, M.; Parker, L. Neergaard; Minow, J. I.

    2013-01-01

    It has been well established that polar orbiting satellites can experience mild to severe auroral charging levels (on the order of a few hundred volts to few kilovolts negative frame potentials) during solar minimum conditions. These same studies have shown a strong reduction in charging during the rising and declining phases of the past few solar cycles with a nearly complete suppression of auroral charging at solar maximum. Recently, we have observed examples of high level charging during the recent approach to Solar Cycle 24 solar maximum conditions not unlike those reported by Frooninckx and Sojka. These observations demonstrate that spacecraft operations during solar maximum cannot be considered safe from auroral charging when solar activity is low. We present a survey of auroral charging events experienced by the Defense Meteorological Satellite Program (DMSP) F16 satellite during Solar Cycle 24 maximum conditions. We summarize the auroral energetic particle environment and the conditions necessary for charging to occur in this environment, we describe how the lower than normal solar activity levels for Solar Cycle 24 maximum conditions are conducive to charging in polar orbits, and we show examples of the more extreme charging events, sometimes exceeding 1 kV, during this time period.

  16. Electron and Proton Auroral Dynamics

    NASA Technical Reports Server (NTRS)

    Mende, S. B.; Frey, H. U.; Gerard, J. C.; Hubert, B.; Fuselier, S.; Spann, J. F., Jr.; Gladstone, R.; Burch, J. L.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    Data from the Wide-band Imaging Camera (WIC) sensitive to far ultraviolet auroras and from the Spectrographic Imager (SI) channel SI12, sensitive to proton precipitation induced Lyman alpha were analyzed during a high altitude orbit segment of the IMAGE spacecraft. This segment began during the expansive phase of a substorm. The aurora changed into a double oval configuration, consisting of a set of discrete pole-ward forms and a separate diffuse auroral oval equatorwards, Although IMF Bz was strongly southward considerable activity could be seen poleward of the discrete auroras in the region that was considered to be the polar cap. The SI12 Doppler shifted Lyman alpha signature of precipitating protons show that the proton aurora is on the equatorward side of the diffuse aurora. In the following several hours the IMF Bz field changed signed. Although the general character of the proton and electron aurora did not change, the dayside aurora moved equatorward when the Bz was negative and more bright aurora was seen in the central polar cap during periods of positive Bz.

  17. The Auroral Particles experiment

    NASA Technical Reports Server (NTRS)

    1981-01-01

    An instrument for the detection of particles in the energy range of 0.1 ev to 80 Kev was designed, built, tested, calibrated, and flown onboard the spacecraft ATS-6. Data from this instrument generated the following research: intensive studies of the plasma in the vicinity of the spacecraft; global variations of plasmas; correlative studies using either other spacecraft or ground based measurements; and studies of spacecraft interactions with ambient plasmas including charging, local electric fields due to differential charging, and active control of spacecraft potential. Results from this research are presented.

  18. ISIS-2 satellite imagery and auroral morphology

    NASA Technical Reports Server (NTRS)

    Anger, C. D.; Murphree, J. S.

    1976-01-01

    Auroral morphology is emphasized over auroral dynamics in a paper describing conspicuous auroral features picked up by the ISIS-2 scanning photometer. Results of improved programs designed to transform the data into a corrected geomagnetic coordinate frame and generate latitude profiles of auroral intensities at different magnetic local times are reported. The diffuse aurora and its relation to the morphology of discrete aurorae is given special attention.

  19. Automatic recognition of auroral forms

    NASA Astrophysics Data System (ADS)

    Pudovkin, Mikhail I.; Steen, Ake; Nikolaev, N. V.; Kornilov, O. I.; Brandstrom, Urban; Gustavsson, Bjorn; Rydesater, Peter

    1999-03-01

    A method for recognition of geometrical shapes in auroral forms is presented. The method is based on the analysis of isolines of auroral luminosity shapes. The basic variables used are the angle, (phi) (s), between the tangent of the contour and the x-axis of an arbitrary coordinate system, and the differential, d(phi) (s), as a function of the distance, s, along the contour. The analysis also includes Fourier transformation of the experimental function d(phi) (s) obtained for the observed auroral forms, and the comparison of the power spectrum, F(k), with those for a series of model contours. Some dynamical characteristics of the aurora are also discussed.

  20. Automatic georeferencing of astronaut auroral photography

    NASA Astrophysics Data System (ADS)

    Riechert, Maik; Walsh, Andrew P.; Gerst, Alexander; Taylor, Matthew G. G. T.

    2016-07-01

    Astronauts on board the International Space Station (ISS) have taken thousands of high-resolution colour photographs of the aurora, which could be made useful for research if their pointing information could be reconstructed. We describe a method to do this using the star field in the images, and how the reconstructed pointing can then be used to georeference the images to a similar level of accuracy in existing all-sky camera images. We have used this method to make georeferenced auroral images taken from the ISS available and here describe the resulting data set, processing software, and how to access them.

  1. Rocket study of auroral processes

    NASA Technical Reports Server (NTRS)

    Arnoldy, R. L.

    1981-01-01

    Abstracts are presented of previously published reports analyzing data from three Echo 3 rocket flights. Particle experiments designed for the Terrier-Malmute flight, the Echo 5 flight, and the Norwegian Corbier Ferdinand 50 flight are described and their flight performance evaluated. Theoretical studies on auroral particle precipitation are reviewed according to observations made in three regions of space: (1) the region accessible to rockets and low altitude satellites (few hundred to a few thousand kilometers); (2) the region extending from 4000 to 8000 km (S3-3 satellite range); and (3) near the equatorial plane (geosynchronous satellite measurements). Questions raised about auroral arc formation are considered.

  2. ULF Waves above the Nightside Auroral Oval during Substorm Onset

    NASA Astrophysics Data System (ADS)

    Rae, I. J.; Watt, C. E. J.

    2016-02-01

    This chapter reviews historical ground-based observations of ultra-low-frequency (ULF) waves tied to substorms, and highlights new research linking these ULF waves explicitly to substorm onset itself. There are several robust methods that can be used to determine the characteristics of a nonstationary time series such as the ULF magnetic field traces observed in the auroral zone during substorms. These include the pure state filter, the Hilbert-Huang transform, and wavelet analysis. The first indication of a substorm is a sudden brightening of one of the quiet arcs lying in the midnight sector of the oval. The chapter focuses on the properties of ULF waves that are seen in two-dimensional images of auroral intensity near substorm expansion phase onset. It also discusses a wider range of magnetotail instabilities that could be responsible for the azimuthally structured auroral forms at substorm onset.

  3. Auroral oval as a beautiful but outdated paradigm

    NASA Astrophysics Data System (ADS)

    Lazutin, Leonid

    2015-03-01

    Auroral oval as an important region of the polar ionosphere presents in a considerable number of a studies of the disturbed magnetosphere. It seems that all about oval is known to all researchers. But there are evidences in a publications that misunderstanding exists and that it is a time for a review on this subject. Most of papers describing auroral position and dynamics were published years ago and became a rarity. We will tell on the history of aurora's distribution before the oval discovery, how the oval was discovered and how it changed our point of view on magnetosphere processes. We will tell also how the oval paradigm grows and haw with time it became non-productive (at our point of view) for a studies of magnetosphere structure and disturbances. Finally we will indicate the position of the aural zone and auroral magnetosphere among the main domains of the magnetosphere.

  4. V and V Efforts of Auroral Precipitation Models: Preliminary Results

    NASA Technical Reports Server (NTRS)

    Zheng, Yihua; Kuznetsova, Masha; Rastaetter, Lutz; Hesse, Michael

    2011-01-01

    Auroral precipitation models have been valuable both in terms of space weather applications and space science research. Yet very limited testing has been performed regarding model performance. A variety of auroral models are available, including empirical models that are parameterized by geomagnetic indices or upstream solar wind conditions, now casting models that are based on satellite observations, or those derived from physics-based, coupled global models. In this presentation, we will show our preliminary results regarding V&V efforts of some of the models.

  5. Finnish Research Activities relevant to IHY

    NASA Astrophysics Data System (ADS)

    Mursula, K.; Kauristie, K.; Vainio, R.

    Space physics is a traditional and strong field of research in Finland dating its early roots back to the mid-19th century i e several decennia before the First International Polar Year in 1882 Measurements of rapid variations of the geomagnetic field started in Helsinki already in 1844 and form now some of the longest and most uniform series of observations measuring the global state of the heliosphere Even further in the north at the Sodankyla Geophysical Observatory SGO continuous measurements span more than 90 years Today space physics activities are conducted mainly in the Universities of Helsinki HU Oulu OU and Turku TU and in the Finnish Meteorological Institute FMI SGO which maintains a versatile set of ground-based instrumentation belongs to OU Although several fields of common interest exist each of these parties also have their own research areas and specific expertise TU has a strong experimental and theoretical program in solar energetic particles HU has a wide program in planetary research as well as in auroral magnetosphere-ionosphere coupling and theoretical space plasma physics OU and SGO have a strong involvement in ionospheric physics as well as in solar-terrestrial and heliospheric physics HU has long been active in space weather projects while OU is a key player in space climate i e in the research of long-term changes in the Sun heliosphere and the near-Earth space As one part of this cosmic rays have been continuously measured in Oulu since 42 years In addition to the versatile ground-based instrumentation

  6. Comparison of ionospheric scintillation statistics from the North Atlantic and Alaskan sectors of the auroral oval using the wideband satellite. Environmental research papers

    SciTech Connect

    Basu, S.; Basu, S.; Livingston, R.C.; Whitney, H.E.; MacKenzie, E.

    1981-09-15

    Phase and amplitude scintillation measurements made at 138 MHz at two widely separated auroral stations, Goose Bay, Labrador, and Anchorage, Alaska, are presented. The phase coherent transmissions obtained from the sun-synchronous Wideband satellite were used for this purpose. The data were obtained for part of the year 1979 during a high sunspot epoch and was terminated by the failure of the Wideband satellite in August, 1979. The primary objective of the report is the presentation of scintillation statistics in a manner required for communications system planning. The morphology at the two stations was found to be significantly different with more nighttime scintillations observed at Goose Bay, while many more daytime scintillations were observed at Anchorage during the same season. The report establishes the existence of L-shell aligned sheets in the daytime in addition to the well-established similar geometry at night. The existence of sheetlike irregularities during the daytime well-equatorward of the auroral oval is significant both from modeling and physical standpoints.

  7. RESEARCH PAPERS : The complex-image method for calculating the magnetic and electric fields produced at the surface of the Earth by the auroral electrojet

    NASA Astrophysics Data System (ADS)

    Boteler, D. H.; Pirjola, R. J.

    1998-01-01

    For studying the auroral electrojet and for examining the effects it can produce in power systems on the ground, it is useful to be able to calculate the magnetic and electric fields that the electrojet produces at the surface of the Earth. Including the effects of currents induced in the Earth leads to a set of integral expressions, the numerical computation of which is complicated and demanding of computer resources. An approximate solution can be achieved by representing the induced currents by an image current at a complex depth. We present a simple derivation of the complex-image expressions and use them to calculate the fields produced by the auroral electrojet at the surface of an earth represented by layered conductivity models. Comparison of these results with ones obtained using the exact integral solution show that the errors introduced are insignificant compared to the uncertainties in the parameters used. The complex-image method thus provides a simple, fast and accurate means of calculating the magnetic and electric fields.

  8. Auroral electrojets and evening sector electron dropouts at synchronous orbit

    NASA Technical Reports Server (NTRS)

    Erickson, K. N.; Winckler, J. R.

    1973-01-01

    Evidence is presented in support of the concept that, during magnetospheric substorms, ionospheric auroral electrojet currents are directly coupled to the proton partial ring current in the outer magnetosphere. It has been found that for sufficiently isolated substorms the timing of the start of the electron dropout and of its maximum depression is in good agreement with the start and maximum of electrojet activity as indicated by the auroral electrojet index. This correlation suggests a direct coupling between the electrojet currents and the proton partial ring current.

  9. Electrodynamic response of the middle atmosphere to auroral pulsations

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.; Croskey, C. L.; Hale, L. C.; Mitchell, J. D.; Barcus, J. R.

    1990-01-01

    The MAC/EPSILON observational campaign encompassed the use of two Nike Orion rocket payloads which studied the effects of auroral energetics on the middle atmosphere. While one payload was launched during the recovery phase of a moderate magnetic substorm, during fairly stable auroral conditions, the other was launched during highly active postbreakup conditions during which Pc5 pulsations were in progress. The energetic radiation of the first event was composed almost entirely of relativistic electrons below 200 keV, while that of the second was dominated by much softer electrons whose high X-ray fluxes exceeded the cosmic ray background as an ionizing source down to below 30 km.

  10. Current Closure in the Auroral Ionosphere: Results from the Auroral Current and Electrodynamics Structure Rocket Mission

    NASA Technical Reports Server (NTRS)

    Kaeppler, S. R.; Kletzing, C. A.; Bounds, S. R.; Gjerloev, J. W.; Anderson, B. J.; Korth, H.; LaBelle, J. W.; Dombrowski, M. P.; Lessard, M.; Pfaff, R. F.; Rowland, D. E.; Jones, S.; Heinselman, C. J.

    2011-01-01

    The Auroral Current and Electrodynamics Structure (ACES) mission consisted of two sounding rockets launched nearly simultaneously from Poker Flat Research Range, AK on January 29, 2009 into a dynamic multiple-arc aurora. The ACES rocket mission was designed to observe electrodynamic and plasma parameters above and within the current closure region of the auroral ionosphere. Two well instrumented payloads were flown along very similar magnetic field footprints, at different altitudes, with small temporal separation between both payloads. The higher altitude payload (apogee 360 km), obtained in-situ measurements of electrodynamic and plasma parameters above the current closure region to determine the input signature. The low altitude payload (apogee 130 km), made similar observations within the current closure region. Results are presented comparing observations of the electric fields, magnetic components, and the differential electron energy flux at magnetic footpoints common to both payloads. In situ data is compared to the ground based all-sky imager data, which presents the evolution of the auroral event as the payloads traversed through magnetically similar regions. Current measurements derived from the magnetometers on the high altitude payload observed upward and downward field-aligned currents. The effect of collisions with the neutral atmosphere is investigated to determine it is a significant mechanism to explain discrepancies in the low energy electron flux. The high altitude payload also observed time-dispersed arrivals in the electron flux and perturbations in the electric and magnetic field components, which are indicative of Alfven waves.

  11. Current Closure in the Auroral Ionosphere: Results from the Auroral Current and Electrodynamics Structure Rocket Mission

    NASA Technical Reports Server (NTRS)

    Kaeppler, S. R.; Kletzing, C. A.; Bounds, S. R.; Gjerloev, J. W.; Anderson, B. J.; Korth, H.; LaBelle, J. W.; Dombrowski, M. P.; Lessard, M.; Pfaff, R. F.; Rowland D. E.; Jones, S.; Heinselman, C. J.

    2012-01-01

    The Auroral Current and Electrodynamics Structure (ACES) mission consisted of two sounding rockets launched nearly simultaneously from Poker Flat Research Range, AK on January 29, 2009 into a dynamic multiple-arc aurora. The ACES rocket mission was designed to observe electrodynamic and plasma parameters above and within the current closure region of the auroral ionosphere. Two well instrumented payloads were flown along very similar magnetic field footprints, at different altitudes, with small temporal separation between both payloads. The higher altitude payload (apogee 360 km), obtained in-situ measurements of electrodynamic and plasma parameters above the current closure region to determine the input signature. The low altitude payload (apogee 130 km), made similar observations within the current closure region. Results are presented comparing observations of the electric fields, magnetic components, and the differential electron energy flux at magnetic footpoints common to both payloads. In situ data is compared to the ground based all-sky imager data, which presents the evolution of the auroral event as the payloads traversed through magnetically similar regions. Current measurements derived from the magnetometers on the high altitude payload observed upward and downward field-aligned currents. The effect of collisions with the neutral atmosphere is investigated to determine if it is a significant mechanism to explain discrepancies in the low energy electron flux. The high altitude payload also observed time-dispersed arrivals in the electron flux and perturbations in the electric and magnetic field components, which are indicative of Alfven waves.

  12. Global Auroral Imaging for the Dynamics Explorer Mission

    NASA Technical Reports Server (NTRS)

    Frank, L. A.

    1998-01-01

    The two Dynamics Explorer spacecraft, DE-1 and DE-2, were launched on August 3, 1981, into polar coplanar orbits at different altitudes for the purpose of studying interactive processes within the atmosphere-ionosphere-magnetosphere system. The DE-1 spacecraft (high-altitude mission) used an elliptical orbit that was selected to allow: (1) measurements extending from the hot magnetospheric plasma through the plasmasphere to the cool ionosphere; (2) global auroral imaging, wave measurements in the heart of the magnetosphere, and crossing of auroral field lines at several earth radii; and (3) measurements for significant periods of time along a magnetic field flux tube. The orbit of Dynamics Explorer 1 offered an opportunity to obtain global images of Earth's dayglow and auroral luminosities and to acquire consecutive images of the entire auroral oval during the growth, onset, expansion, and recovery phases of substorms. The University of Iowa's Spin-scan Auroral Imaging (SAI) instrument, was on-board DE-1. SAI was activated in orbit and placed in routine operation on September 23, 1981, and has provided outstanding new contributions in the fields of auroral, magnetospheric and geocoronal physics, introduced a powerful tool for the study of global atmospheric ozone, and initiated the first search from space for marine bioluminescence on the surface of the global ocean. The SAI instrumentation consists of three imaging photometers, two for visible wavelengths and the third for vacuum-ultraviolet wavelengths equipped with primary catoptric optics with superpolished mirror surfaces. The primary focusing element is an off-axis section of a parabolic mirror that is used to provide an optical path completely free of support structures for the mirrors.

  13. The auroral footprint of Enceladus on Saturn.

    PubMed

    Pryor, Wayne R; Rymer, Abigail M; Mitchell, Donald G; Hill, Thomas W; Young, David T; Saur, Joachim; Jones, Geraint H; Jacobsen, Sven; Cowley, Stan W H; Mauk, Barry H; Coates, Andrew J; Gustin, Jacques; Grodent, Denis; Gérard, Jean-Claude; Lamy, Laurent; Nichols, Jonathan D; Krimigis, Stamatios M; Esposito, Larry W; Dougherty, Michele K; Jouchoux, Alain J; Stewart, A Ian F; McClintock, William E; Holsclaw, Gregory M; Ajello, Joseph M; Colwell, Joshua E; Hendrix, Amanda R; Crary, Frank J; Clarke, John T; Zhou, Xiaoyan

    2011-04-21

    Although there are substantial differences between the magnetospheres of Jupiter and Saturn, it has been suggested that cryovolcanic activity at Enceladus could lead to electrodynamic coupling between Enceladus and Saturn like that which links Jupiter with Io, Europa and Ganymede. Powerful field-aligned electron beams associated with the Io-Jupiter coupling, for example, create an auroral footprint in Jupiter's ionosphere. Auroral ultraviolet emission associated with Enceladus-Saturn coupling is anticipated to be just a few tenths of a kilorayleigh (ref. 12), about an order of magnitude dimmer than Io's footprint and below the observable threshold, consistent with its non-detection. Here we report the detection of magnetic-field-aligned ion and electron beams (offset several moon radii downstream from Enceladus) with sufficient power to stimulate detectable aurora, and the subsequent discovery of Enceladus-associated aurora in a few per cent of the scans of the moon's footprint. The footprint varies in emission magnitude more than can plausibly be explained by changes in magnetospheric parameters--and as such is probably indicative of variable plume activity.

  14. Statistical study of NEIAL occurence in the PFISR data and correlated auroral forms

    NASA Astrophysics Data System (ADS)

    Michell, R. G.; Samara, M.

    2012-12-01

    Naturally Enhanced Ion Acoustic Lines (NEIALs) have been observed wth the Poker Flat Incoherent Scatter Radar (PFISR) ever since it began operating in 2006. The first few years of PFISR operation corresponded to a long, geomagnetically quiet solar minimum. During this time there were only a limited number of NEIALs observed with PFISR with simultaneous auroral imaging. The increases in solar activity that started occurring in 2011 and 2012 have resulted in significantly more active auroral structures over the PFISR radar at Poker Flat, AK. The increase in auroral activity has resulted in a large number of NEIALs observed with PFISR. The MOOSE imagers have been operating continuously since September 2011 and have made many auroral observations simultaneous to the PFISR observations of NEIALs. The larger number of NEIAL observations available now, make it possible to distinguish the range of auroral features that are associated with different aspects of the NEIAL observations. We aim to statistically catagorize the different types of auroral features that occur with NEIALs in the PFISR data, with the goal of gaining insight into the possible generation mechanisms of NEIALs.; PFISR electron density measurements (in 10^11 m^-3) showing strong NEIAL enhancements extending to greater than 700 km altitudes. ; All-sky image from 22 January 2012, showing tall rayed auroral structures at a time of strong NEIALs in the PFISR data.

  15. Luminosity variations in several parallel auroral arcs before auroral breakup

    NASA Astrophysics Data System (ADS)

    Safargaleev, V.; Lyatsky, W.; Tagirov, V.

    1997-08-01

    Variation of the luminosity in two parallel auroral arcs before auroral breakup has been studied by using digitised TV-data with high temporal and spatial resolution. The intervals when a new arc appears near already existing one were chosen for analysis. It is shown, for all cases, that the appearance of a new arc is accompanied by fading or disappearance of another arc. We have named these events out-of-phase events, OP. Another type of luminosity variation is characterised by almost simultaneous enhancement of intensity in the both arcs (in-phase event, IP). The characteristic time of IP events is 10-20 s, whereas OP events last about one minute. Sometimes out-of-phase events begin as IP events. The possible mechanisms for OP and IP events are discussed.

  16. Mapping thermospheric winds in the auroral zone

    NASA Astrophysics Data System (ADS)

    Conde, M.; Smith, R. W.

    A new all-sky imaging Fabry-Perot (ASIFP) spectrometer has been developed for ground-based mapping of upper atmospheric wind and temperature fields in the auroral zone. Although several other ASIFP spectrometers exist for atmospheric studies [Rees et al., 1984; Sekar et al., 1993; Biondi et al., 1995] these instruments have all operated with etalons of fixed optical gap, a method potentially subject to errors in the presence of auroral intensity gradients. In this instrument the etalon plate spacing is scanned periodically over one order of interference and each photon detected is assigned to a wavelength interval which is determined from both its arrival location on the detector and the etalon plate spacing prevailing at the detection time. Spectra accumulated this way are not distorted by spatial intensity gradients. Preliminary λ630 nm observations were made during the winter of 1994/95 from Poker Flat Research Range, Alaska. To illustrate some of the features we have observed in this study we present line-of-sight wind estimates derived for the night of December 7, 1994. The background wind matches averages presented previously by Sica et al. [1986] and is consistent with winds driven principally by momentum deposition from ionospheric plasma convection through ion-drag. Smaller scale curvature and divergence features are also discernable and are discussed.

  17. Further Studies of Flickering Auroral Roar

    NASA Astrophysics Data System (ADS)

    Ye, S.; Labelle, J.; Weatherwax, A.

    2004-12-01

    In December 2002, a Versatile Electromagnetic Wave Receiver (VIEW) was deployed at South Pole station. This system records HF waveforms continuously for up to 6 hours/day. Summary files are examined weekly by Dartmouth personnel, and interesting time intervals are saved to CD-rom. This interactive experimental method provides extremely high time- and frequency-resolution measurements of auroral radio emissions, while discarding data from times when no events occur. The motivation was to measure three types of auroral radio emissions: Auroral Roar, a relatively narrowband (δf/f <0.1) emission near 2 and 3 times the F region ionospheric electron cyclotron frequency (fce); Auroral Hiss, a whistler mode wave emission with frequencies lower than 1MHz. ; and Auroral medium frequency (MF) burst, broadband impulsive radio emissions observed at ground level during the breakup phase of auroral substorms. In the year of 2003, we recorded about 80 minutes of auroral roar emission, consisting of 40 different events, at South Pole station. Hughes and LaBelle [2001] observed the first flickering auroral roar, with a ~10 Hz pulsation in emission strength, in Greenland. They proposed that these pulsations are related to the electron flux modulations similar to those which cause flickering aurora. By examining all 80 minutes (40 events) of auroral roar captured in 2003, we found more than 10 cases of flickering auroral roar from 10 different days. However, most instances were brief, sometimes only a few seconds. The total time of flickering auroral roar was a few minutes (a few percent of the total time of occurrence of auroral roar emissions). We also observed the first ever example of higher frequency flickering auroral roar, with a modulation frequency around 100 Hz. We investigate these events by taking time series of the strength of the auroral roar emissions, taking Fourier transforms to determine the frequencies of the flickering. In this poster, we show statistics of the

  18. Magnetospheric and auroral plasmas: A short survey of progress, 1971 - 1975

    NASA Technical Reports Server (NTRS)

    Frank, L. A.

    1975-01-01

    Milestones in researches of auroral and magnetospheric plasmas for the past quadrennium 1971 - 1975 are reviewed. Findings, including those of the polar cusp, the polar wind, the explosive disruptions of the magnetotail, the interactions of hot plasmas with the plasmapause, the auroral field-aligned currents, and the striking 'inverted-V' electron precipitation events, are reported. Solutions to major questions concerning the origins and acceleration of these plasmas are discussed. A comprehensive bibliography of current research is included.

  19. Magnetotail energy dissipation during an auroral substorm.

    PubMed

    Panov, E V; Baumjohann, W; Wolf, R A; Nakamura, R; Angelopoulos, V; Weygand, J M; Kubyshkina, M V

    2016-12-01

    Violent releases of space plasma energy from the Earth's magnetotail during substorms produce strong electric currents and bright aurora. But what modulates these currents and aurora and controls dissipation of the energy released in the ionosphere? Using data from the THEMIS fleet of satellites and ground-based imagers and magnetometers, we show that plasma energy dissipation is controlled by field-aligned currents (FACs) produced and modulated during magnetotail topology change and oscillatory braking of fast plasma jets at 10-14 Earth radii in the nightside magnetosphere. FACs appear in regions where plasma sheet pressure and flux tube volume gradients are non-collinear. Faster tailward expansion of magnetotail dipolarization and subsequent slower inner plasma sheet restretching during substorm expansion and recovery phases cause faster poleward then slower equatorward movement of the substorm aurora. Anharmonic radial plasma oscillations build up displaced current filaments and are responsible for discrete longitudinal auroral arcs that move equatorward at a velocity of about 1km/s. This observed auroral activity appears sufficient to dissipate the released energy.

  20. Magnetotail energy dissipation during an auroral substorm

    PubMed Central

    Panov, E.V.; Baumjohann, W.; Wolf, R.A.; Nakamura, R.; Angelopoulos, V.; Weygand, J. M.; Kubyshkina, M.V.

    2016-01-01

    Violent releases of space plasma energy from the Earth’s magnetotail during substorms produce strong electric currents and bright aurora. But what modulates these currents and aurora and controls dissipation of the energy released in the ionosphere? Using data from the THEMIS fleet of satellites and ground-based imagers and magnetometers, we show that plasma energy dissipation is controlled by field-aligned currents (FACs) produced and modulated during magnetotail topology change and oscillatory braking of fast plasma jets at 10-14 Earth radii in the nightside magnetosphere. FACs appear in regions where plasma sheet pressure and flux tube volume gradients are non-collinear. Faster tailward expansion of magnetotail dipolarization and subsequent slower inner plasma sheet restretching during substorm expansion and recovery phases cause faster poleward then slower equatorward movement of the substorm aurora. Anharmonic radial plasma oscillations build up displaced current filaments and are responsible for discrete longitudinal auroral arcs that move equatorward at a velocity of about 1km/s. This observed auroral activity appears sufficient to dissipate the released energy. PMID:27917231

  1. Magnetotail energy dissipation during an auroral substorm

    NASA Astrophysics Data System (ADS)

    Panov, E. V.; Baumjohann, W.; Wolf, R. A.; Nakamura, R.; Angelopoulos, V.; Weygand, J. M.; Kubyshkina, M. V.

    2016-12-01

    Violent releases of space plasma energy from the Earth's magnetotail during substorms produce strong electric currents and bright aurora. But what modulates these currents and aurora and controls dissipation of the energy released in the ionosphere? Using data from the THEMIS fleet of satellites and ground-based imagers and magnetometers, we show that plasma energy dissipation is controlled by field-aligned currents (FACs) produced and modulated during magnetotail topology change and oscillatory braking of fast plasma jets at 10-14 Earth radii in the nightside magnetosphere. FACs appear in regions where plasma sheet pressure and flux tube volume gradients are non-collinear. Faster tailward expansion of magnetotail dipolarization and subsequent slower inner plasma sheet restretching during substorm expansion and recovery phases cause faster poleward then slower equatorward movement of the substorm aurora. Anharmonic radial plasma oscillations build up displaced current filaments and are responsible for discrete longitudinal auroral arcs that move equatorward at a velocity of about 1 km s-1. This observed auroral activity appears sufficient to dissipate the released energy.

  2. Theoretical and experimental studies relevant to interpretation of auroral emissions

    NASA Technical Reports Server (NTRS)

    Keffer, Charles E.

    1991-01-01

    The accomplishments achieved over the past year are detailed with emphasis on the interpretation or auroral emissions and studies of potential spacecraft-induced contamination effects. Accordingly, the research was divided into two tasks. The first task is designed to add to the understanding of space vehicle induced external contamination. An experimental facility for simulation of the external environment for a spacecraft in low earth orbit was developed. The facility was used to make laboratory measurements of important phenomena required for improving the understanding of the space vehicle induced external environment and its effect on measurement of auroral emissions from space-based platforms. A workshop was sponsored to provide a forum for presentation of the latest research by nationally recognized experts on space vehicle contamination and to discuss the impact of this research on future missions involving space-based platforms. The second task is to add an ab initio auroral calculation to the extant ionospheric/thermospheric global modeling capabilities. Once the addition of the code was complete, the combined model was to be used to compare the relative intensities and behavior of various emission sources (dayglow, aurora, etc.). Such studies are essential to an understanding of the types of vacuum ultraviolet (VUV) auroral images which are expected to be available within two years with the successful deployment of the Ultraviolet Imager (UVI) on the ISTP POLAR spacecraft. In anticipation of this, the second task includes support for meetings of the science working group for the UVI to discuss operational and data analysis needs. Taken together, the proposed tasks outline a course of study designed to make significant contributions to the field of space-based auroral imaging.

  3. A new auroral boundary determination algorithm based on observations from TIMED/GUVI and DMSP/SSUSI

    NASA Astrophysics Data System (ADS)

    Ding, Guang-Xing; He, Fei; Zhang, Xiao-Xin; Chen, Bo

    2017-02-01

    An automatic auroral boundary determination algorithm is proposed in this study based on the partial auroral oval images from the Global Ultraviolet Imager (GUVI) aboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics satellite and the Special Sensor Ultraviolet Spectrographic Imager (SSUSI) aboard the Defense Meteorological Satellite Program (DMSP F16). This algorithm based on the fuzzy local information C-means clustering segmentation can be used to extract the auroral oval poleward and equatorward boundaries from merged images with filled gaps from both GUVI and SSUSI. Both extracted poleward and equatorward boundary locations are used to fit the global shape of the auroral oval with a off-center quasi-elliptical fitting technique. Comparison of the extracted auroral oval boundaries with those identified from the DMSP SSJ observations demonstrates that this new proposed algorithm can reliably be used to construct the global configuration of auroral ovals under different geomagnetic activities at different local times. The statistical errors of magnetic latitudes of the fitted auroral oval boundaries were generally less than 3° at 2 sigma and indicate that the the fitted boundaries agree better with b2e and b5e than b1e and b6 boundaries. This proposed algorithm provides us with a useful tool to extract the global shape and position of the auroral oval from the partial auroral images.

  4. The 2013 Saturn auroral campaign

    NASA Astrophysics Data System (ADS)

    Melin, Henrik; Badman, Sarah; Khurana, Krishan

    2016-01-01

    Saturn's aurorae are intriguing displays of light caused by charged particles impacting the upper atmosphere. Observations of the aurora therefore reveal the interaction between the dynamic magnetosphere and atmosphere. The Cassini spacecraft's exploration of the Saturn system since 2004 has provided unprecedented opportunities to study the solar wind-magnetosphere-ionosphere coupling at Saturn. This opportunity was fully exploited during the auroral observation campaign which took place in spring 2013, the results from which form the topic of this Icarus special issue.

  5. Auroral signature of comet Shoemaker-Levy 9 in the jovian magnetosphere.

    PubMed

    Prangé, R; Engle, I M; Clarke, J T; Dunlop, M; Ballester, G E; Ip, W H; Maurice, S; Trauger, J

    1995-03-03

    The electrodynamic interaction of the dust and gas comae of comet Shoemaker-Levy 9 with the jovian magnetosphere was unique and different from the atmospheric effects. Early theoretical predictions of auroral-type processes on the comet magnetic field line and advanced modeling of the time-varying morphology of these lines allowed dedicated observations with the Hubble Space Telescope Wide Field Planetary Camera 2 and resulted in the detection of a bright auroral spot. In that respect, this observation of the surface signature of an externally triggered auroral process can be considered as a "magnetospheric active experiment" on Jupiter.

  6. Interactive Auroral Science for Hearing-Impaired Students

    NASA Astrophysics Data System (ADS)

    Samara, M.; Michell, R. G.; Jahn, J.; Pfeifer, M.; Ibarra, S.; Hampton, D. L.; Powell, D.

    2012-12-01

    Under a NASA E/PO grant, we have partnered with San Antonio's Sunshine Cottage School for Deaf Children to develop a science class experience where students directly interact with scientists and participate in a research-grade space science measurement campaign. The unique aspect of partnering with Sunshine Cottage lies in Sunshine's approach of auditory-verbal communication. Aided by technology (hearing aids, cochlear implants), a diverse student body with students of all levels of hearing loss (moderate through profound) is taught in an entirely auditory-verbal environment at Sunshine Cottage. Bringing these students into early contact with research work can lay the foundation for future careers in the STEM field that normally they might not consider as indicated by the first year of this collaboration where the student response was distinctly positive. Here we report on the first year of those activities, as they related to a ground based imaging approach to exploring the northern lights and from the point of view of the scientists that participated. The major components of that activity included a site visit to SwRI by the students and their teachers, a semester long lab at school utilizing current research tools and a real-time campaign night. The students used a number of diagnostics to first predict and then verify auroral activity. One of the tools used was the MOOSE observatory which is a community resource state of the art observatory comprised of 5 EMCCD imagers in Alaska, established through an NSF MRI grant. We will discuss the approach and lessons learned during the first year of the project and the directions that we will likely take in the second year. Lessons learned from teaching these students space science related topic can be flowed right back into mainstream classroom settings. One other significant and unexpected aspect of this first year was that we were able to connect two groups of students through skype (in the 4th to 5th grades) that

  7. The relationship between the magnetosphere and magnetospheric/auroral substorms

    NASA Astrophysics Data System (ADS)

    Akasofu, S.-I.

    2013-03-01

    On the basis of auroral and polar magnetic substorm studies, the relationship between the solar wind-magnetosphere dynamo (the DD dynamo) current and the substorm dynamo (the UL dynamo) current is studied. The characteristics of both the DD and UL currents reveal why auroral substorms consist of the three distinct phases after the input power ɛ is increased above 1018 erg s-1. (a) The growth phase; the magnetosphere can accumulate magnetic energy for auroral substorms, when the ionosphere cannot dissipate the power before the expansion phase. (b) The expansion phase; the magnetosphere releases the accumulated magnetic energy during the growth phase in a pulse-like manner in a few hours, because it tries to stabilize itself when the accumulated energy reaches to about 1023 erg s-1. (c) The recovery phase; the magnetosphere becomes an ordinary dissipative system after the expansion phase, because the ionosphere becomes capable of dissipating the power with the rate of 1018 ~ 1019 erg s-1. On the basis of the above conclusion, it is suggested that the magnetosphere accomplishes the pulse-like release process (resulting in spectacular auroral activities) by producing plasma instabilities in the current sheet, thus reducing the current. The resulting contraction of the magnetic field lines (expending the accumulated magnetic energy), together with break down of the "frozen-in" field condition at distances of less than 10 RE, establishes the substorm dynamo that generates an earthward electric field (Lui and Kamide, 2003; Akasofu, 2011). It is this electric field which manifests as the expansion phase. A recent satellite observation at a distance of as close as 8.1 RE by Lui (2011) seems to support strongly the occurrence of the chain of processes suggested in the above. It is hoped that although the concept presented here is very crude, it will serve in providing one way of studying the three phases of auroral substorms. In turn, a better understanding of auroral

  8. Mesoscale ionospheric tomography at the Auroral region

    NASA Astrophysics Data System (ADS)

    Luntama, J.; Kokkatil, G. V.

    2008-12-01

    FMI (Finnish Meteorological Institute) has used observations from the dense GNSS network in Finland for high resolution regional ionospheric tomography. The observation system used in this work is the VRS (Virtual Reference Station) network in Finland operated by Geotrim Ltd. This network contains 86 GNSS ground stations providing two frequency GPS and GLONASS observations with the sampling rate of 1 Hz. The network covers the whole Finland and the sampling of the ionosphere is very good for observing mesoscale ionospheric structures at the Auroral region. The ionospheric tomography software used by FMI is the MIDAS (Multi-Instrument Data Analysis System) algorithm developed and implemented by the University of Bath (Mitchell and Spencer, 2003). MIDAS is a 3-D extension of the 2-D tomography algorithm originally presented by Fremouw et al. (1992). The research at FMI is based on ground based GNSS data collected in December 2006. The impacts of the two geomagnetic storms during the month are clearly visible in the retrieved electron density and TEC maps and they can be correlated with the magnetic field disturbances measured by the IMAGE magnetometer network. This is the first time that mesoscale structures in the ionospheric plasma can be detected from ground based GNSS observations at the Auroral region. The continuous high rate observation data from the Geotrim network allows monitoring of the temporal evolution of these structures throughout the storms. Validation of the high resolution electron density and TEC maps is a challenge as independent reference observations with a similar resolution are not available. FMI has compared the 3-D electron density maps against the 2-D electron density plots retrieved from the observations from the Ionospheric Tomography Chain operated by the Sodankylä Geophysical Observatory (SGO). Additional validation has been performed with intercomparisons with observations from the ground based magnetometer and auroral camera network

  9. Evolution of Jupiter's auroral-related stratospheric heating and chemistry

    NASA Astrophysics Data System (ADS)

    Sinclair, James; Orton, Glenn S.; Greathouse, Thomas K.; Fletcher, Leigh N.; Moses, Julianne I.; Hue, Vincent; Irwin, Patrick Gerard Joseph; Melin, Henrik; Giles, Rohini Sara

    2016-10-01

    Auroral processes on Jupiter are evident over a large range of wavelengths. Emission at X-ray, UV and near-infrared wavelengths highlights the precipitation of charged particles in Jupiter's ionosphere. Jupiter's auroral regions also exhibit enhanced mid-infrared emission of CH4 (7.8-μm), C2H2 (13-μm), C2H4 (10.5-μm) and C2H6 (12.2-μm), which indicates auroral processes modify the thermal structure and chemistry of the neutral stratosphere at pressures from 10 mbar to 10 μbar. In Sinclair et al., 2016a (submitted), 2016b (in preparation), we investigated these processes further by performing a retrieval analysis of Voyager-IRIS (Infrared Interferometer Spectrometer) observations measured in November 1979, Cassini-CIRS (Composite Infrared Spectrometer) observations measured in January 2001 and IRTF-TEXES (Texas Echelon Cross Echelle Spectrograph on NASA's Infrared Telescope Facility) spectra measured in December 2014. These datasets however captured Jupiter at significantly different epochs and thus the overall global evolution of atmospheric conditions as well as differences in spatial sampling, spectral resolution (and therefore vertical resolution in the atmosphere) have made inferences of the temporal evolution in auroral regions a challenge. However, in April 2016, we acquired IRTF-TEXES observations of Jupiter's high latitudes, using observing parameters very similar to those in December 2014. By performing a similar analysis of these observations and comparing results between December 2014 and April 2016, we can investigate the evolution of the thermal structure and chemistry in Jupiter's auroral regions over a 15 month timescale. The magnitude of temperature/composition changes and the altitudes at which they occur will provide insights into how auroral processes in the ionosphere propagate to the stratosphere. In particular, we can assess whether the evolution of stratospheric conditions in auroral regions is related to the decrease in solar activity

  10. Birth and life of auroral arcs embedded in the evening auroral oval convection: A critical comparison of observations with theory

    NASA Astrophysics Data System (ADS)

    Haerendel, G.; Frey, H. U.; Chaston, C. C.; Amm, O.; Juusola, L.; Nakamura, R.; Seran, E.; Weygand, J. M.

    2012-12-01

    We present and analyze data on auroral arcs obtained during a pass of the FAST satellite over the field-of-view of the all-sky camera at Ft. Simpson (Canada), supported by ground-based magnetometer and SuperDARN radar data, and plasma data from THEMIS-A near the source region of the auroral currents. The auroral event took place at 19:00 MLT during substorm activity further east. Active auroral arcs were present over six degrees in latitude moving equatorward with significant changes in brightness and structure. New arcs were forming continuously at the polar border of the auroral oval which was marked by an Alfvénic arc. The data analysis revealed that the equatorward drift of the arcs was in part due to convective motion of the plasma frame but was rather dominated by proper motions of the arcs. Interpretation of these findings in the framework of theoretical work by one of the authors reproduces quantitatively the observed proper motion as a consequence of the progressive erosion of magnetic shear stresses. Most important was the possibility to deduce the interaction time scale between arc and source region. On average it corresponded to about six to eight transit times of an Alfvén wave between arc and source plasma or two fundamental eigenperiods of toroidal mode or azimuthally polarized Alfvén waves. However, large variations of the interaction times and corresponding proper motions were found. They are attributed to temporal and spatial variations of the energy input from the source plasma. The more remarkable is the fact that analysis on the basis of a quasi-stationary model produces consistent results. The progressive release of shear stresses during the equatorward motion of the arcs leads to the conclusion that they are dying after having reached the maximum of the poleward Pedersen current.

  11. Auroral origin of medium scale gravity waves in neutral composition and temperature

    NASA Technical Reports Server (NTRS)

    Chandra, S.; Spencer, N. W.; Krankowsky, D.; Laemmerzahl, P.

    1979-01-01

    The kinetic temperature and neutral composition data obtained from the Aeros B neutral atmosphere temperature experiment and the neutral and ion mass spectrometer show spatial structures characteristic of medium scale gravity waves with a wavelength in the range of several hundred kilometers. These waves are associated with auroral activity, and their spatial structure reflects the time history of the auroral electrojet. The medium scale gravity waves tend to propagate to mid-latitudes on the nightside. On the dayside their range is limited to high latitudes. Gravity waves are carriers of auroral energy to middle and low latitudes where they may cause irreversible changes in temperature via viscous dissipation. Since auroral activity occurs frequently, it is suggested that this energy reaches the mid-latitude region of the thermosphere much more frequently than is indicated by planetary magnetic indices.

  12. Automatic Georeferencing of Astronaut Auroral Photography

    NASA Astrophysics Data System (ADS)

    Walsh, A. P.; Riechert, M.; Taylor, M. G.

    2014-12-01

    Astronauts on board the International Space Station have taken thousands of high quality photographs of the aurorae borealis and australis with a high temporal and spatial resolution. A barrier to these photographs being used in research is that the cameras do not have a fixed orientation and the images therefore do not have any pointing information associated with them. Using astrometry.net and other open source libraries we have developed a software toolkit to automatically reconstruct the pointing of the images from the visible starfield and hence project the auroral images in geographic and geomagnetic coordinates. Here we explain the technique and the resulting data products, which will soon be publically available through the project website.

  13. Temporal and spatial characteristics of auroral energy deposition

    NASA Astrophysics Data System (ADS)

    Hampton, D. L.; Conde, M.

    2015-12-01

    Auroral electron precipitation forms a complex and dynamic energy input into the high-latitude ionosphere and thermopshere. Rapid changes in plasma density due to electron impact ionization create correspondingly rapid changes in conductivity which in turn change the magnitude and altitude profile of magnetospheric current closure in the E- and F-region. Modeling these changes in the ionosphere and their effects on the local or regional upper atmosphere requires detailed input over wide regions. In support of the AMISR PINOT campaign and several rocket campaigns (CASCADES-2, MICA, ASSP) we have developed and tested a method to determine the characteristics of auroral energy input using purely ground-based optical measurements in geometries away from magnetic zenith. Using the N2+ first negative emissions at 427.8 nm reproduces the total energy flux over a wide region, but alone does not indicate the altitude profile of this energy deposition. Using temperature maps of the E-region collected by a Scanning Doppler Imager (SDI) observing the auroral green-line emission is a proxy for the characteristic energy of the precipitating electrons. While in some cases the energy determination underestimates the average energy it still is a good proxy for understanding when the electron distribution changes. We examine two seasons worth of auroral observations and determine the spatial and temporal variability of auroral energy deposition in comparison to solar wind and geophysical activity parameters. We also compare the results with well-known empirical models of electron energy deposition and show that they underestimate the peak local energy deposition rates by as much as a factor of 30.

  14. Electron precipitation in the midday auroral oval

    SciTech Connect

    Meng, C.

    1981-04-01

    Simultaneous observations of auroral displays and electron precipitations by the DMSP 33 satellite provide an excellent and unique opportunity to study precipitation characteristics of the midday auroral oval. Attention is given to two topics: (1) the nature of the 'gap' of the midday discrete auroras which is a permanent feature of the dayside auroral oval observed by both Isis 2 and DMSP satellites and (2) the relationship of this gap with the polar cusp region. Based on 2-month (June, July 1975) observations of the midday auroras over the southern hemisphere, it is found that inside the 'gap' of the discrete auroras along the dayside auroral oval, soft electron precipitations with a magnetosheathlike spectrum were invariably detected. The spatial extent of this region was about few degrees in latitude and about 2--3 hours in local time near 1130 magnetic local time meridian. No significant electron precipitation was detected poleward of the instantaneous midday auroral oval. Typical plasma sheet and discrete auroral types of electron precipitations were detected in the other parts of the midday auroral oval. Therefore it is proposed that the ionospheric projection of the polar cusp is a small region of the instantaneous dayside auroral oval near the noon meridian, coinciding with the 'gap' of the midday discrete auroras.

  15. Auroral Substorm Time Scales: Seasonal and IMF Variations

    NASA Technical Reports Server (NTRS)

    Chua, D.; Parks, G. K.; Brittnacher, M.; Germany, G. A.; Spann, J. F.; Six, N. Frank (Technical Monitor)

    2002-01-01

    The time scales and phases of auroral substorm, activity are quantied in this study using the hemispheric power computed from Polar Ultraviolet Imager (UVI) images. We have applied this technique to several hundred substorm events and we are able to quantify how the characterist act, of substorms vary with season and IMF Bz orientation. We show that substorm time scales vary more strongly with season than with IMF Bz orientation. The recovery time for substorm. activity is well ordered by whether or not the nightside oral zone is sunlit. The recovery time scales for substorms occurring in the winter and equinox periods are similar and are both roughly a factor of two longer than in summer when the auroral oval is sunlit. Our results support the hypothesis that the ionosphere plays an active role in governing the dynamics of the aurora.

  16. Electron cyclotron waves in the presence of parallel electric fields in the Earthś auroral plasma

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Dixit, S. K.; Gwal, A. K.

    1997-01-01

    The electron cyclotron waves that originate at low altitudes (<0.5 RE) and observed by ground facilities have been studied in the presence of a weak parallel electric field in auroral magnetoplasma consisting of trapped energetic auroral electrons and cold background electrons of ionospheric origin. The model distribution for auroral trapped electrons is taken as Maxwellian ring distribution. An expression for the growth rate has been obtained in the presence of parallel electric field assuming that the real frequency in the whistler mode is not affected by the presence of the electric field. The results show that waves grow (or damp) in amplitude for a parallel (or antiparallel) electric field. The influence of the electric field is more pronounced at a shorter wavelength spectrum. An increase in population of energetic electrons increases the growth rate and thus, plays a significant role in the wave excitation process in the auroral regions. Acknowledgements. The authors are grateful to Prof. D. J. Southwood (Imperial College, London), J. C. Samson (University of Alberta, Edmonton), L. J. Lanzerotti (AT&T Bell Laboratories), A. Wolfe (New York City Technical College) and to Dr. M. Vellante (University of LÁquila) for helpful discussions. They also thank Dr. A. Meloni (Istituto Nazionale di Geofisica, Roma) who made available geomagnetic field observations from LÁquila Geomagnetic Observatory. This research activity at LÁquila is supported by MURST (40% and 60% contracts) and by GIFCO/CNR. Topical Editor K.-H. Glaßmeier thanks C. Waters and S. Fujita for their help in evaluating this paper.-> Correspondence to :P. Francia->

  17. Study of Motion of the Auroral Oval During September 30 - October 4, 2012 Geomagnetic Storm. A Project of National Secondary School Competition in Scientific Research on Antarctica "Feria Antarctica Escolar 2014", organized by Chilean Antarctic Institute (INACH).

    NASA Astrophysics Data System (ADS)

    Stepanova, M. V.; Cabezas-Escares, J. F.; Letelier-Ulloa, T. C.; Ortega-Letelier, P.

    2014-12-01

    Changes in the position of the auroral oval during the development of the September 30 - October 4, 2012 geomagnetic storm in both Northern and Southern Hemispheres were studied using the data of the Dynamics Explorer Satellite Mission (DMSP). In particular, the location of b1e, b1i, b2e, and b2i boundaries defined by Newell at al. [1996], was obtained from the electron and ion precipitating fluxes, measured by the SSJ/4 particle detectors onboard the F16, F17, and F18 satellites.According to Newell at al. [1996], these boundaries represent the zero-energy convection boundary (b1e,b1i), and the precipitating energy flux maximum (b2e,b2i). It was found that during the main phase of the strom, on average, all boundaries move towards the equator, and return to its previous location during recovery phase. Deviations from the common trend could be related to the changes in the solar wind conditions. This study was done by the Secondary school students Javiera Cabezas-Escares and Tamara Letelier Ulloa from Lyceum N°1 Javiera Carrera in frame of the National Secondary School Competition in the Scientific Research on Antarctica "Feria Antarctica Escolar" organized by Chilean Antarctic Institute. It was supervised by their Physics teacher Pablo Ortega Letelier and by Marina Stepanova, researcher from Universidad de Santiago de Chile.

  18. Auroral images from Spacelab 3

    NASA Technical Reports Server (NTRS)

    Hallinan, Thomas J.; Lind, Don

    1987-01-01

    The Spacelab 3 space shuttle mission of April 29 to May 6, 1985, provided an excellent opportunity to survey the Aurora Australis from near-Earth orbit. The orbital inclination and Beta angle were such that the orbit penetrated the average auroral oval in darkness. 274 color photographs of the aurora and approximately 5 hr of black and white video recordings were obtained. The data cover 22 separate passes from seven days. On several occasions the Orbiter passed above the auroral forms. By using the orbital motion to provide the parallax, both the color photographs and the video recordings were viewed stereoscopically. The data provide the first views from outside the atmosphere of thin horizontal layers of enhanced aurora. The layers, once thought to be rare, were recorded on two out of three passes. This first observation of enhanced aurora from space eliminates concerns that the ground-based observations might have been an optical illusion caused by atmospheric refraction. Also, for the first time, vertically thin layers were observed in diffuse aurora. This is a measurement that is possible only from space ideally in near-Earth orbit.

  19. Determining the source region of auroral emissions in the prenoon oval using coordinated Polar BEAR UV-imaging and DMSP particle measurements

    NASA Technical Reports Server (NTRS)

    Newell, Patrick T.; Meng, CHING-I.; Huffman, Robert E.

    1992-01-01

    The Polar Beacon Experiment and Auroral Research (Polar BEAR) satellite included the capability for imaging the dayside auroral oval in full sunlight at several wavelengths. Particle observations from the DMSP F7 satellite during dayside auroral oval crossings are compared with approximately simultaneous Polar BEAR 1356-A images to determine the magnetospheric source region of the dayside auroral oval. The source region is determined from the DMSP particle data, according to recent work concerning the classification and identification of precipitation source regions. The close DMSP/Polar BEAR coincidences all occur when the former satellite is located between 0945 and 1000 MLT. Instances of auroral arcs mapping to each of several different regions, including the boundary plasma sheet, the low-latitude boundary layer, and the plasma mantle were found. It was determined that about half the time the most prominent auroral arcs are located at the interfaces between distinct plasma regions, at least at the local time studied here.

  20. Compound auroral micromorphology: ground-based high-speed imaging

    NASA Astrophysics Data System (ADS)

    Kataoka, Ryuho; Fukuda, Yoko; Miyoshi, Yoshizumi; Miyahara, Hiroko; Itoya, Satoru; Ebihara, Yusuke; Hampton, Donald; Dahlgren, Hanna; Whiter, Daniel; Ivchenko, Nickolay

    2015-02-01

    Auroral microphysics still remains partly unexplored. Cutting-edge ground-based optical observations using scientific complementary metal-oxide semiconductor (sCMOS) cameras recently enabled us to observe the fine-scale morphology of bright aurora at magnetic zenith for a variety of rapidly varying features for long uninterrupted periods. We report two interesting examples of combinations of fine-scale rapidly varying auroral features as observed by the sCMOS cameras installed at Poker Flat Research Range (PFRR), Alaska, in February 2014. The first example shows that flickering rays and pulsating modulation simultaneously appeared at the middle of a surge in the pre-midnight sector. The second example shows localized flickering aurora associated with growing eddies at the poleward edge of an arc in the midnight sector.

  1. Direction finding measurements of auroral kilometric radiation

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.; Baumback, M. M.; Gurnett, D. A.

    1974-01-01

    Direction finding measurements with plasma wave experiments onboard the Hawkeye-1 and IMP-8 satellites were used to locate the source region of auroral kilometric radiation. The radiation exhibits peak intensities between about 100 kHz and 300 kHz, and emits intense sporadic bursts lasting for between one half hour to several hours. The total power emitted in this frequency range exceeds 10 to the 9th power watts at peak intensity. The occurrence of the radiation is known to be closely associated with bright auroral arcs which occur in the local evening auroral regions.

  2. Weak auroral emissions and particle precipitations in the dusk auroral oval

    SciTech Connect

    Ono, T.; Hirasawa, T. ); Ching-I. Meng )

    1989-09-01

    Faint auroral displays in the low-latitude region of the duskside auroral oval were examined by using 5577 A, 6300 A, and 4861 A auroral images from three monochromatic all-sky television cameras at Syowa Station, Antarctica, and simultaneous precipitating auroral particle data obtained by the U.S. Air Force/Defense Meteorological Satellite Program (USAF/DMSP) F6 satellite. In the low-latitude region of the duskside auroral oval, we found three types of auroral displays with weak optical intensity: (1) proton auroras, (2) pulsating auroras, and (3) faint discrete auroral arcs distinct only in the 6300 A emission. In usual cases, the energy input into this region is mostly carried y proton precipitations to produce proton auroras mainly at wavelengths of 4861 A and 5577 A. Pulsating features are sometimes observed in the diffuse auroral region in the dusk sector. Comparing auroral images with the nearly simultaneous data of precipitating auroral particles, we confirmed that the pulsating auroras are associated with the intensification of precipitating electron flux from the central plasma sheet. Furthermore, electrons are the main contributors to the energy input into the duskside auroral oval in this case. We also found that discrete auroras sometimes appeared in the 6300 A images, but not in images at other wavelengths. They appear in the equatorial part of the dusk auroral oval. These 6300 A discrete auroras correspond to weak precipitation spikes of low-energy electrons simultaneously measured by DMSP satellites. The flux and average energy of these electron spikes are about 10{sup 8}/(cm{sup 2} sr s) and 100 eV, respectively. They are intense enough to excite 6300 A emissions but not 5577 A emissions, as detected from the ground observations. {copyright} American Geophysical Union 1989

  3. Planning and Conducting Research Activities.

    ERIC Educational Resources Information Center

    Christiansen, Richard L.

    1983-01-01

    Some directions and influences on dental research activities in the near future are discussed. Current challenges include international competition, fellowships, and equipment. Potential research activity includes preventive medicine, epidemiology, chronic illness, the elderly, bioengineering, materials research, nutrition, soft tissue research,…

  4. Analysis of Auroral Data from Nasa's 1968 and 1969 Airborne Auroral Expedition

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Results of a methodical compilation, reduction, and correlated analysis of spectrophotometric data obtained by various scientific groups during NASA's 1968 and 1969 Airborne Auroral Expedition are presented.

  5. One kilometer tether observations of auroral electric fields

    NASA Astrophysics Data System (ADS)

    Watanabe, Shigeto; Whalen, Brian A.

    The OEDIPUS (Observations of Electric-field Distributions in the Ionospheric Plasma - a Unique Strategy) rocket was launched on January 30, 1989 from the Andoya range in Norway to an apogee of 512 km during an active auroral display. Two payloads, fully instrumented with plasma diagnostics but connected by a conducting tether were separated in flight along geomagnetic field lines to a distance of 1 km. Energetic electron, ion and thermal ion observations at the both ends of the payload were made in and near several auroral forms. Tether (interpayload) voltages and currents were monitored by using a high impedance voltmeter and a low impedance ammeter. Results of comparisons between charged particle observations and the tether voltage and current measurements indicate clearly the validity of electric field measurements made by this technique.

  6. Effects of magnetic-storm phases on F-layer irregularities from auroral to equatorial latitudes. Quarterly report, 1 Oct-31 Dec 90

    SciTech Connect

    Aarons, J.; Mendillo, M.

    1990-12-31

    Partial Contents: The effects of electric field and ring current energy increases on F-layer irregularities at auroral and sub-auroral latitudes; The role of the ring current in generating or inhibiting equatorial F-layer irregularities during magnetic storms; Auroral and sub-auroral F-layer irregularities and high plasma convection during the magnetically active periods of September 17-24, 1984; and Simultaneous All-Sky Optical Airglow Imaging Observations and San Marco Satellite Measurements in the Pacific Sector.

  7. Cassini UVIS Auroral Observations in 2016

    NASA Astrophysics Data System (ADS)

    Pryor, Wayne R.; Jouchoux, Alain; Esposito, Larry W.; Radioti, Aikaterini; Grodent, Denis; Gustin, Jacques; Gerard, Jean-Claude; Lamy, Laurent; Badman, Sarah; Bunce, Emma; Cecconi, Baptiste; Clarke, John T.; Crary, Frank; Dougherty, Michele; Dyudina, Ulyana A.; Kurth, William; Mitchell, Don; Nichols, Jonathan; Prange, Renee; Schippers, Patricia; Zarka, Philippe; Cassini UVIS Team

    2016-10-01

    In June of 2016, the Cassini Saturn orbiter began a series of high inclination orbits that will continue until September 2017 when the mission ends as Cassini enters the Saturn atmosphere. These orbits present excellent views of Saturn's polar regions suitable for auroral imaging at the closest distances to date, with the additional prospect of simultaneous particle and fields measurements within the sources of Saturn Kilometric Radiation (SKR) associated with ultraviolet auroral emissions and/or acceleration regions likely coinciding with them. We will present new Cassini Ultraviolet Imaging Spectrograph (UVIS) auroral images, spectra and movies obtained during the summer and fall of 2016 and put them in the context of auroral data collected since Cassini orbit insertion in 2004. Included in the new data will be UVIS south polar observations obtained simultaneously with Hubble Space Telescope observations of the north polar region on June 29, 2016 and August 19, 2016.

  8. OVATION Prime Model and "Aurorasaurus" Auroral Observations

    NASA Video Gallery

    This video shows the auroral oval, as modeled using OVATION Prime (2013), along with citizen science reports collected by the Aurorasaurus project for the St. Patrick’s Day storm over March 17-19, ...

  9. Comment: An Apparent Controversy in Auroral Physics

    NASA Astrophysics Data System (ADS)

    Haerendel, Gerhard

    2007-03-01

    In his article ``A turning point in auroral physics,'' Bryant argued against what he called the `standard' theory of auroral acceleration, according to which the electrons ``gain their energy from static electric fields,'' and offered wave acceleration as an alternative. Because of the importance of the process, not only for the aurora borealis but also for other cosmic plasmas, a clarification of this apparent controversy seems to be in place.

  10. Electromagnetic plasma wave emissions from the auroral field lines

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.

    1977-01-01

    The most important types of auroral radio emissions are reviewed, both from a historical perspective as well as considering the latest results. Particular emphasis is placed on four types of electromagnetic emissions which are directly associated with the plasma on the auroral field lines. These emissions are (1) auroral hiss, (2) saucers, (3) ELF noise bands, and (4) auroral kilometric radiation. Ray tracing and radio direction finding measurements indicate that both the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances from about 2.5 to 5 R sub e. For the auroral hiss the favored mechanism appears to be amplified Cerenkov radiation. For the auroral kilometric radiation several mechanisms have been proposed, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.

  11. Auroral kilometric radiation/aurora correlation

    NASA Technical Reports Server (NTRS)

    Benson, R. F.; Akasofu, S. I.

    1983-01-01

    Auroral kilometric radiation (AKR) observations from the ISIS 1 topside sounder receiver were compared with visual auroral observations from the network of Alaskan all-sky camera stations. The goal was to relate AKR source region encounters to specific auroral forms on the same magnetic field line. Thirty-eight simultaneous data sets were identified and analyzed. In general, intense AKR was associated with bright auroral arcs and conditions of weak or no AKR corresponded to times when either no aurora or only a faint arc or weak diffuse aurora were observed. Five cases, when both intense AKR and bright visual aurora were present, were analyzed in detail. Complete electron density N sub e contours, from the satellite altitude down to the F region ionization peak, were obtained along N-S traversals of the AKR source region. In addition, the ISIS 1 orbital tracks were projected down the magnetic field lines to the auroral altitude and compared to auroral features on a map derived from the all sky camera images. Density cavities (regions where N sub e 100/cu cm) were encountered on each of these passes.

  12. ESA's Cluster solved an auroral puzzle

    NASA Astrophysics Data System (ADS)

    2003-05-01

    investigation at the University of California, Berkeley, United States, now looks forward to a new way of studying the Earth’s protective shield. He says, “This result has opened up a new area of research. We can now watch dayside proton aurorae and use those observations to know where and how the cracks in the magnetic field are formed and how long the cracks remain open. That makes it a powerful tool to study the entry of the solar wind into the Earth’s magnetosphere.” The Earth’s interaction with the Sun is a current focus of scientific attention because of its importance in knowing how the Sun affects the Earth, most notably our climate. Also, while not immediately dangerous to us on Earth, it is also important for quantifying the danger to satellites, which can be damaged or destroyed by powerful solar flares. Note to Editors: Proton aurorae were globally imaged for the first time by NASA’s IMAGE spacecraft. The images revealed the presence of the ‘dayside proton auroral spots’. By a fortunate coincidence, IMAGE and Cluster both spotted the event on 18 March 2002. Combining with IMAGE’s observations, Cluster made it possible to establish the ground truth of the phenomenon. The paper on these results, Simultaneous Cluster and IMAGE Observations of Cusp Reconnection and Auroral Spot for Northward IMF by Tai Phan and 24 other authors will be published in Geophysical Research Letters, 21 May 2003, Vol. 30, No. 10. The principal investigators responsible for the instruments that made these results possible are: Henri Rème of CESR/Toulouse, France (Cluster Proton Detectors), Andre Balogh of Imperial College, London, United Kingdom (Cluster Magnetic Field Instrument) and Stephen Mende of University of California, Berkeley, United States (IMAGE/FUV). More about Cluster ESA’s Cluster is a collection of four spacecraft, launched on two Russian rockets during the summer of 2000. They are now flying in formation around the Earth, relaying the most detailed ever

  13. ELF waves generated by modulated HF heating of the auroral electrojet and observed at a ground distance of ˜4400 km

    NASA Astrophysics Data System (ADS)

    Moore, R. C.; Inan, U. S.; Bell, T. F.; Kennedy, E. J.

    2007-05-01

    We present calibrated measurements of ELF waves generated by modulated HF heating of the auroral electrojet by the High frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska, and detected after propagating more than 4400 km in the Earth-ionosphere waveguide to Midway Atoll. The magnitude of the 2125 Hz wave received at Midway Atoll is consistent with the radiation from a horizontal dipole located at the altitude of the maximum Hall conductivity variation (created by modulated HF heating) and radiating ˜4-32 W. The HF-ELF conversion efficiency at HAARP is thus estimated to be ˜0.0004-0.0032% for the 2125 Hz wave generated using sinusoidal amplitude modulation.

  14. Auroral effects on meteoric metals in the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Heinselman, Craig James

    1999-12-01

    Meteors deposit many tons of material into Earth's upper atmosphere each day. The physics and chemistry of meteoric metals in the atmosphere have long been active topics of study, but sophisticated models have emerged just recently of the gas-phase chemical reactions that affect the evolution of the state of these metals. At high latitudes, this portion of the upper atmosphere is also shared by the aurora borealis, or northern lights, which dramatically alter the properties of the background plasma. This thesis concerns coupled chemical models and one- dimensional dynamical models that were developed to investigate the effects of auroral ionization on the time evolution of meteoric iron and sodium elements and compounds in the upper atmosphere. These models are used to show that aurorae can result in rapid ionization of recently deposited iron and sodium, with time constants on the order of 15 minutes. The models are also used to investigate the influence of aurorae on the background iron and sodium layers. Because of the nominal altitude of the neutral iron layer, aurorae will not normally have a measurable impact on that constituent. For sodium, on the other hand, the impact is more significant but highly dependent on the chemical makeup of the aurorally produced ions. For either case, sporadic neutral atom layers at auroral altitudes are significantly affected. A case study of radar and lidar measurements from the Sondrestrom Facility in Greenland is used to test the sodium model. Results are presented which are consistent with the model predictions of the effects of the aurorally enhanced ionization. For this specific case, evidence is also presented to support a gas-phase chemical mechanism for the formation of a thin the formation of a thin sporadic sodium layer.

  15. Effects of Interplanetary Shock Inclinations on Nightside Auroral Power Intensity

    NASA Astrophysics Data System (ADS)

    Oliveira, D. M.; Raeder, J.; Tsurutani, B. T.; Gjerloev, J. W.

    2016-02-01

    We derive fast forward interplanetary (IP) shock speeds and impact angles to study the geoeffectiveness of 461 IP shocks that occurred from January 1995 to December 2013 using ACE and Wind spacecraft data. The geomagnetic activity is inferred from the SuperMAG project data. SuperMAG is a large chain which employs more than 300 ground stations to compute enhanced versions of the traditional geomagnetic indices. The SuperMAG auroral electroject SME index, an enhanced version of the traditional AE index, is used as an auroral power (AP) indicator. AP intensity jumps triggered by shock impacts are correlated with both shock speed and impact angle. It is found that high AP intensity events typically occur when high speed IP shocks impact the Earth's magnetosphere with the shock normal almost parallel to the Sun-Earth line. This result suggests that symmetric and strong magnetospheric compression leads to favorable conditions for intense auroral power release, as shown previously by simulations and observations. Some potential mechanisms will be discussed.

  16. Polarisation of the auroral red line in the Earth's upper atmosphere: a review (Invited)

    NASA Astrophysics Data System (ADS)

    Lamy, H.; Barthelemy, M.; Lilensten, J.; Bommier, V.; Simon Wedlund, C.

    2013-12-01

    Polarisation of light is a key observable to provide information about asymmetry or anisotropy within a radiative source. Polarimetry of auroral emission lines in the Earth's upper atmosphere has been overlooked for decades. However, the bright red auroral line (6300Å) produced by collisional impact with electrons precipitating along magnetic field lines is a good candidate to search for polarisation. This problem was investigated recently with observations obtained by Lilensten et al (2008), Barthélemy et al (2011) and Lilensten et al (2013) with a photopolarimeter. Analysis of the data indicates that the red auroral emission line is polarised at a level of a few percent. The results are compared to theoretical predictions of Bommier et al (2011) that were obtained for a collimated beam. The comparison suggests the existence of depolarization processes whose origin will be discussed. A new dedicated spectropolarimeter currently under development will also be presented. This instrument will cover the optical spectrum from approximately 400 to 700 nm providing simultaneously the polarisation of the red line and of other interesting auroral emission lines such as N2+ 1NG (4278Å), other N2 bands, etc... The importance of these polarisation measurements in the context of upper atmosphere modelling and geomagnetic activity will be discussed. Lilensten, J. et al, Polarization in aurorae: A new dimension for space environments studies, Geophys. Res. Lett., 26, 269, 2008 Barthélemy M. et al, Polarisation in the auroral red line during coordinated EISCAT Svalbard Radar/optical experiments, Annales Geophysicae, Volume 29, Issue 6, 2011, 1101-1112, 2011. Bommier V. et al, The Theoretical Impact Polarization of the O I 6300 Å Red Line of Earth Auroræ, Annales Geophysicae, Volume 29, Issue 1, 2011, 71-79, 2011 Lilensten, J. et al, The thermospheric auroral red line polarization: confirmation of detection and first quantitative analysis, Journal of Space Weather and Space

  17. Auroral resonance line radiative transfer

    SciTech Connect

    Gladstone, G.R. )

    1992-02-01

    A model is developed for simulating the two-dimensional radiative transfer of resonance line emissions in auroras. The method of solution utilizes Fourier decomposition of the horizontal dependence in the intensity field so that the two-dimensional problem becomes a set of one-dimensional problems having different horizontal wavenumbers. The individual one-dimensional problems are solved for using a Feautrier-type solution of the differential-integral form of the radiative transfer equation. In the limit as the horizontal wavenumber becomes much larger than the local line-center extinction coefficient, the scattering integral becomes considerably simplified, and the final source function is evaluated in closed form. The two-dimensional aspects of the model are tested against results for nonresonance radiative transfer studies, and the resonance line part of the model is tested against results of existing plane-parallel resonance line radiative transfer codes. Finally, the model is used to simulate the intensity field of O{sub I} 1,304{angstrom} for hard and soft auroras of various Gaussian horizontal widths. The results demonstrate the importance of considering the effects of two-dimensional radiative transfer when analyzing auroral resonance line data.

  18. Variation of Jupiter's aurora observed by Hisaki/EXCEED: 2. Estimations of auroral parameters and magnetospheric dynamics

    NASA Astrophysics Data System (ADS)

    Tao, Chihiro; Kimura, Tomoki; Badman, Sarah V.; André, Nicolas; Tsuchiya, Fuminori; Murakami, Go; Yoshioka, Kazuo; Yoshikawa, Ichiro; Yamazaki, Atsushi; Fujimoto, Masaki

    2016-05-01

    Jupiter's auroral parameters are estimated from observations by a spectrometer EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) on board Japanese Aerospace Exploration Agency's Earth-orbiting planetary space telescope Hisaki. EXCEED provides continuous auroral spectra covering the wavelength range over 80-148 nm from the whole northern polar region. The auroral electron energy is estimated using a hydrocarbon color ratio adopted for the wavelength range of EXCEED, and the emission power in the long wavelength range 138.5-144.8 nm is used as an indicator of total emitted power before hydrocarbon absorption and auroral electron energy flux. The quasi-continuous observations by Hisaki provide the auroral electron parameters and their relation under different auroral activity levels. Short- (within < one planetary rotation) and long-term (> one planetary rotation) enhancements of auroral power accompany increases of the electron number flux rather than the electron energy variations. The relationships between the auroral electron energy (~70-400 keV) and flux (1026-1027/s, 0.08-0.9 μA/m2) estimated from the observations over a 40 day interval are in agreement with field-aligned acceleration theory when incorporating probable magnetospheric parameters. Applying the electron acceleration theory to each observation point, we explore the magnetospheric source plasma variation during these power-enhanced events. Possible scenarios to explain the derived variations are (i) an adiabatic variation of the magnetospheric plasma under a magnetospheric compression and/or plasma injection, and (ii) a change of the dominant auroral component from the main emission (main aurora) to the emission at the open-closed boundary.

  19. Sounding rocket study of auroral electron precipitation

    SciTech Connect

    McFadden, J.P.

    1985-01-01

    Measurement of energetic electrons in the auroral zone have proved to be one of the most useful tools in investigating the phenomena of auroral arc formation. This dissertation presents a detailed analysis of the electron data from two sounding rocket campaigns and interprets the measurements in terms of existing auroral models. The Polar Cusp campaign consisted of a single rocket launched from Cape Parry, Canada into the afternoon auroral zone at 1:31:13 UT on January 21, 1982. The results include the measurement of a narrow, magnetic field aligned electron flux at the edge of an arc. This electron precipitation was found to have a remarkably constant 1.2 eV temperature perpendicular to the magnetic field over a 200 to 900 eV energy range. The payload also made simultaneous measurements of both energetic electrons and 3-MHz plasma waves in an auroral arc. Analysis has shown that the waves are propagating in the upper hybrid band and should be generated by a positive slope in the parallel electron distribution. A correlation was found between the 3-MHz waves and small positive slopes in the parallel electron distribution but experimental uncertainties in the electron measurement were large enough to influence the analysis. The BIDARCA campaign consisted of two sounding rockets launched from Poker Flat and Fort Yukon, Alaska at 9:09:00 UT and 9:10:40 UT on February 7, 1984.

  20. High Frequency Active Auroral Research Program (HAARP) imager. Final report, 29 August 1991-29 August 1993

    SciTech Connect

    Lance, C.; Eather, R.

    1993-09-30

    A low-light-level monochromatic imaging system was designed and fabricated which was optimized to detect and record optical emissions associated with high-power rf heating of the ionosphere. The instrument is capable of detecting very low intensities, of the order of 1 Rayleigh, from typical ionospheric atomic and molecular emissions. This is achieved through co-adding of ON images during heater pulses and subtraction of OFF (background) images between pulses. Images can be displayed and analyzed in real time and stored in optical disc for later analysis. Full image processing software is provided which was customized for this application and uses menu or mouse user interaction.

  1. Environmental Impact Analysis Process. Final Environmental Impact Statement. Part 2. Proposed High Frequency Active Auroral Research Program.

    DTIC Science & Technology

    1993-07-01

    which I will identify by page number. Nikola Tesla , built huge facilities early in this century to study electricity and the earth’s ability to...I believe you have left out some critical points which the public will want to have answers to before construction and operation begin. Like Tesla ...based on the proposed tax laws), then it would be helpful to have a BTU equivalent for the facility and its components as well. 11-4 Like Tesla , the

  2. The Auroral Zone: A citizen science project to classify auroral imaging data

    NASA Astrophysics Data System (ADS)

    Chaddock, D.; Spanswick, E.; Gillies, D. M.; Quinney, A.; Donovan, E.; Murray, M. S.

    2015-12-01

    Currently, over 40 million images of the aurora have been recorded by University of Calgary all-sky imagers. Analysis of these images is an important and crucial step in the advancement of auroral physics. The number of images waiting to be analyzed is expected to increase dramatically with the introduction of TREx (Transition Region Explorer), a new high resolution imaging network set to be deployed in late 2016. In order to classify large amounts of images in a short period of time, we have designed a citizen science project aimed at engaging the general public in auroral science, called "The Auroral Zone". This project facilitates a symbiotic relationship between the scientific community and the general public. Using the data from this website, a large database of classified auroral images will be created and then used for future analysis by the scientific community. In exchange, the general public can learn about the aurora and contribute to auroral physics in a tangible way. The ultimate aim of this project is to create an ever expanding database of all-sky images classified by arc type (i.e. single arc, diffuse aurora, multiple arc, etc.) and filtered for adverse viewing conditions (i.e. snow, rain, light pollution, etc). We aim to introduce "The Auroral Zone" into the school systems to interest young scientists in the spectacular natural phenomenon that defines the Canadian North. "The Auroral Zone" is a collaborative project between the University of Calgary, Canadian Space Agency, AuroraMAX, and Aurorasaurus.

  3. First light from a kilometer-baseline Scintillation Auroral GPS Array

    PubMed Central

    Datta-Barua, S; Su, Y; Deshpande, K; Miladinovich, D; Bust, G S; Hampton, D; Crowley, G

    2015-01-01

    We introduce and analyze the first data from an array of closely spaced Global Positioning System (GPS) scintillation receivers established in the auroral zone in late 2013 to measure spatial and temporal variations in L band signals at 100–1000 m and subsecond scales. The seven receivers of the Scintillation Auroral GPS Array (SAGA) are sited at Poker Flat Research Range, Alaska. The receivers produce 100 s scintillation indices and 100 Hz carrier phase and raw in-phase and quadrature-phase samples. SAGA is the largest existing array with baseline lengths of the ionospheric diffractive Fresnel scale at L band. With an initial array of five receivers, we identify a period of simultaneous amplitude and phase scintillation. We compare SAGA power and phase data with collocated 630.0 nm all-sky images of an auroral arc and incoherent scatter radar electron precipitation measurements, to illustrate how SAGA can be used in multi-instrument observations for subkilometer-scale studies. Key Points A seven-receiver Scintillation Auroral GPS Array (SAGA) is now at Poker Flat, Alaska SAGA is the largest subkilometer array to enable phase/irregularities studies Simultaneous scintillation, auroral arc, and electron precipitation are observed PMID:26709318

  4. Magnetic storm effects on F layer irregularities near the auroral oval

    SciTech Connect

    Aarons, J.; Rodger, A.S.

    1987-05-01

    The effect of F layer irregularities on trans-ionospheric transmissions and fading at HF at equatorial, auroral, and polar latitudes has been documented. Little has been done on morphology and physics of irregularities noted at sub-auroral latitudes, in the vicinity of the plasmapause. The intensities of the irregularities are considerably less than those observed at equatorial and high latitude regions. The scatterers in this region are at times correlated with magnetic activity and at other times present during periods of low magnetic activity, including the recovery phase of magnetic storms.

  5. The response of thermospheric nitric oxide to an auroral storm. II - Auroral latitudes

    NASA Technical Reports Server (NTRS)

    Siskind, D. E.; Barth, C. A.; Evans, D. S.; Roble, R. G.

    1989-01-01

    NOAA 6 and 7 particle measurements are used, in conjunction with a statistical model of the auroral particle precipitation, to study the response of auroral NO to the auroral storm of September 19, 1984. The results of a time-dependent photochemical calculation show that particle precipitation can more effectively produce NO than can Joule heating, in contrast to nonauroral latitudes where heating is important. Both the model and the NO data show NO increases as a result of the storm; however, the absolute magnitude of the NO in the model, as well as the amplitude of the increase, significantly exceeded what was observed. Two possible explanations for the this discrepancy are proposed.

  6. Modulation of auroral electrojet currents using dual HF beams with ELF phase offset

    NASA Astrophysics Data System (ADS)

    Golkowski, M.; Cohen, M.; Moore, R. C.

    2012-12-01

    The modulation of naturally occuring ionospheric currents with high power radio waves in the high frequency (HF, 3-10 MHz) band is a well known technique for generation of extremely low frequency (ELF, 3-3000 Hz) and very low frequency (VLF, 3-30 kHz) waves. We use the heating facility of the High Frequency Active Auroral Research Program (HAARP) to investigate the effect of using dual HF beams with an ELF/VLF phase offset between the modulation waveforms. Experiments with offset HF beams confirm the model of independent ELF/VLF sources. Experiments with co-located HF beams exhibit interaction between the first and second harmonics of the modulated tones when square and sine wave modulation waveforms are employed. Using ELF/VLF phase offsets for co-loacted beams is also shown to be a potential diagnostic for the D-region ionospheric profile.

  7. Very low frequency waves stimulated by an electron accelerator in the auroral ionosphere

    NASA Technical Reports Server (NTRS)

    Holtet, J. A.; Pran, B. K.; Egeland, A.; Grandal, B.; Jacobsen, T. A.; Maehlum, B. N.; Troim, J.

    1981-01-01

    The sounding rocket, Polar 5, carrying a 10 keV electron accelerator in a mother-daughter configuration and other diagnostic instruments, was launched into a slightly disturbed ionosphere with weak auroral activity on February 1, 1976 from Northern Norway to study VLF wave phenomena. The rocket trajectory crossed two auroral regions: one, between 86 and 111 s flight time, and a secondary region between 230 and 330 s. The daughter, carrying the accelerator, was separated axially from the mother in a forward direction at an altitude of 90 km. The VLF experiment, carried by the mother payload, recorded both electromagnetic and electrostatic waves. The receiving antenna was an electric dipole, 0.3 m tip-to-tip, oriented 90 degrees to the rocket spin axis. The onboard particle detector recorded increased electron fluxes in the two auroral regions. A double peaked structure was observed in the fluxes of 4-5 and 12-27 keV electrons within the northern auroral form. The number density of thermal plasma varied during the flight, with maximum density within the main auroral region. To the north of this aurora a slow, steady decrease in the density was observed, with no enhancement in the region of the second aurora.

  8. Global auroral responses to magnetospheric compressions by shocks in the solar wind: Two case studies

    NASA Technical Reports Server (NTRS)

    Craven, J. D.; Frank, L. A.; Russell, C. T.; Smith, E. J.; Lepping, R. P.

    1985-01-01

    The global auroral responses to shocks in the solar wind at Earth were studied. The z-component of the interplanetary magnetic field, Bz, is negative ahead and behind the first shock and positive for the second case. A sudden-commencement geomagnetic storm develops in each case, with maximum D sub st 190 nT. An immediate auroral response is detected at all longitudes around the auroral oval, in which auroral luminosities increase by a factor of 2 to 3 with the first samples after each sudden commencement. The time delay in obtaining the first sample varies with local time from approx. 1 to 18 mins. No other significant variations in the aurora are associated with the immediate response. Beginning approx. 30 mins after each sudden commencement, the aurora becomes active and displays significant variations in its luminosity and spatial distribution. For Bz 0 an intense substorm develops. A sun-aligned transpolar arc forms when Bz 0, appearing first at local midnight as a polar arc and then lengthening sunward from the auroral oval across the polar cap to noon at an average speed of approx. 1 km/sec.

  9. An auroral VxO: A reappraisal of need and call for community input

    NASA Astrophysics Data System (ADS)

    Germany, G. A.

    2007-12-01

    Space-based auroral imagery provides our best way of specifying the global deposition of energy in the coupled ionosphere-thermosphere via precipitation, as well as the global state of the magnetosphere. These images complement global data products built from networks of ground-based radars, all-sky imagers, magnetometers, riometers, etc. There is thus a perceived need to develop ways to intercompare and integrate data from different imagers, and to compare image data with other data products. Virtual observatories (VxO's) provide an opportunity to share data and to provide a framework for intercomparison of auroral image data with other data sources. The author, working with international collaborators, has previously proposed to build on existing collaborations with online data providers to develop a virtual observatory for space-based auroral image data that will work with, and complement, existing VxO efforts. The proposed efforts would allow researchers and other virtual observatories to survey and access data from all space-based auroral imagers, to integrate data from different imagers with each other, and to set the technical stage for ultimate integration with other global data products (such as SuperDARN, SuperMag, VGMO, Gloria, etc). The proposed work would also complement other online efforts, such as the efforts of the Canadian Space Sciences Data Portal (CSSDP), SuperDARN, and the evolving network of NASA supported virtual observatories. While the auroral VxO concept has been well-received, previous efforts to make that concept a reality have faced questions about the degree to which an auroral VxO is needed and the degree to which the auroral imaging community is willing to participate in such an observatory. This paper presents the expected advantages of an auroral VxO, discusses potential tools and architectures needed in such an observatory, and outlines the level of community involvement needed to make it a reality. The paper is intended to open

  10. A Survey of Known Indicators of Auroral Substorm Onset.

    DTIC Science & Technology

    1985-08-29

    the aa index (instead of Kp) with the overall periodicity of the sunspot cycle every 11 years, the results of which are shown in Figure 2. The aa ...of 54 aa indices for a 27 -day rotation with the set of 54 aa indices for the next 27 -day rotation and assigned this correlation coefficient for the...diffuse auroral belts in Antarctica, in Report of Ionosphere and Space Research in Japan, 29:149-152. 19 INVARIANT LATITIU ~(3 1t(51 J =-~ (4) • ’ (6) aa (1

  11. Auroral Phenomena: Associated with auroras in complex ways are an extraordinary number of other physical phenomena.

    PubMed

    O'brien, B J

    1965-04-23

    The array of auroral phenomena involves all the basic types of physical phenomena: heat, light, sound, electricity and magnetism, atomic physics, and plasma physics. The uncontrollability, the unreproducibility, and the sheer enormity of the phenomena will keep experimentalists and theorists busy but unsatisfied for many years to come. The greatest challenge in this field of research is an adequate experimentally verifiable theory of the local energization of auroral particle fluxes. Once that is achieved, there is every likelihood that the multitude of correlations between auroral phenomena can be understood and appreciated. Until that time, however, such correlations are to be regarded like icebergs-the parts that can be seen are only a small fraction of the whole phenomenon, and it is the large unseen parts that can be dangerous to theorists and experimentalists alike.

  12. Ground-based interferometric studies of auroral roar

    NASA Astrophysics Data System (ADS)

    Hughes, John Mark

    2000-09-01

    Auroral roar is a naturally-occurring radio emission generated in the Earth's auroral ionosphere at frequencies near 3 MHz and 4.5 MHz and believed to occur at harmonics of the ionsopheric electron cyclotron frequency (2 fce and 3fce). Although the first observations of auroral roar were reported more than 20 years ago, a satisfactory mechanism for generating the emissions has not been found. A principle reason for this is that previous studies have been made using non- directional antennas which give no information about the location of the auroral roar source regions. This thesis describes the development of the medium- frequency interferometer (MFI), the first direction- sensitive instrument capable of detecting auroral roar events, and discusses a series of experiments designed to study the generation mechanism and propagation characteristics of 2fce auroral roar. Data from the MFI reveal that auroral roar is generated in both the bottom and top sides of the ionsopheric F-region and that it can propagate to the ground from both these locations. The data also reveal that individual auroral roar events often propagate to the MFI from more than one direction, implying the existence of more than one source region. Statistical and case study analyses suggest that auroral roar is usually generated near the poleward edge of the auroral oval. Electron density measurements from the Sondrestrom incoherent scatter radar have been used to test one candidate generation mechanism which suggests that 2fce auroral roar is generated as an electrostatic upper hybrid wave at places where the upper hybrid frequency matches twice the electron cyclotron frequency. In each of the five available cases, this matching condition is met in the auroral roar source region. Finally, observations and numerical simulations of a recently observed phenomenon known as flickering auroral roar are presented. Numerical simulations suggest that flickering auroral roar may be caused by auroral

  13. A real-time hybrid aurora alert system: Combining citizen science reports with an auroral oval model

    NASA Astrophysics Data System (ADS)

    Case, N. A.; Kingman, D.; MacDonald, E. A.

    2016-06-01

    Accurately predicting when, and from where, an aurora will be visible is particularly difficult, yet it is a service much desired by the general public. Several aurora alert services exist that attempt to provide such predictions but are, generally, based upon fairly coarse estimates of auroral activity (e.g., Kp or Dst). Additionally, these services are not able to account for a potential observer's local conditions (such as cloud cover or level of darkness). Aurorasaurus, however, combines data from the well-used, solar wind-driven, OVATION Prime auroral oval model with real-time observational data provided by a global network of citizen scientists. This system is designed to provide more accurate and localized alerts for auroral visibility than currently available. Early results are promising and show that over 100,000 auroral visibility alerts have been issued, including nearly 200 highly localized alerts, to over 2000 users located right across the globe.

  14. Multi-spacecraft Observation of Auroral Kilometric Radiation

    NASA Astrophysics Data System (ADS)

    Romantsova, T. V.; Mogilevsky, M. M.; Hanasz, J.; Skalsky, A. A.; Rusanov, A. A.

    The Auroral Kilometric Radiation observed typically at frequencies centered around 250kHz is generated in the night sector of the EarthSs magnetosphere and is closely linked with geomagnetic activities. The present study takes an advantage of the si- multaneous wave observations onboard POLAR, GEOTAIL, INTERBALL-1 and -2 spacecraft which have different locations in the near-EarthSs space. Comparative anal- ysis of AKR observations made at different locations from the source region brings an important information on the AKR wave modes, source region characteristics and plasma properties along the way of emission propagation. Work supported by grant INTAS 99-1006 and RFBR 02-02-1753

  15. Tangential electric fields in a drifting auroral arc

    NASA Astrophysics Data System (ADS)

    Yau, A. W.; Whalen, B. A.; Creutzberg, F.

    1981-04-01

    Rocket-borne ion convection velocity and ground-based optical measurements in an early evening, equatorward drifting, NW-SE oriented auroral arc are reported. Measurements indicate a detailed correspondence between the normal component of the ion convection velocity (the component normal to the auroral arc) and the drift motion of the auroral arc. The two velocities were identical on a time scale of minutes, and correlated strongly with each other in smaller-scale temporal variations. The correspondence implies a near-zero tangential electric field in an auroral arc, in the frame of reference of the arc. The observations have serious consequences for several auroral theories.

  16. Drifts of auroral structures and magnetospheric electric fields

    SciTech Connect

    Nakamura, Rumi; Oguti, Takasi )

    1987-10-01

    Drifts of pulsating auroral patches and discrete auroral arc fragments are analyzed on the basis of all-sky TV observations of auroras. The drifts of auroral structures in this study correspond on a gross scale with other measurements of magnetospheric convection. The result strongly suggests that not only auroral patches but also arc fragments, when detached from the main body of the discrete aurora, drift owing to the magnetospheric electric fields. The measurement of the drifts of auroral structures could possibly provide us with a convenient and accurate method to estimate the magnetospheric electric fields.

  17. An Earth-like correspondence between Saturn's auroral features and radio emission.

    PubMed

    Kurth, W S; Gurnett, D A; Clarke, J T; Zarka, P; Desch, M D; Kaiser, M L; Cecconi, B; Lecacheux, A; Farrell, W M; Galopeau, P; Gérard, J-C; Grodent, D; Prangé, R; Dougherty, M K; Crary, F J

    2005-02-17

    Saturn is a source of intense kilometre-wavelength radio emissions that are believed to be associated with its polar aurorae, and which provide an important remote diagnostic of its magnetospheric activity. Previous observations implied that the radio emission originated in the polar regions, and indicated a strong correlation with solar wind dynamic pressure. The radio source also appeared to be fixed near local noon and at the latitude of the ultraviolet aurora. There have, however, been no observations relating the radio emissions to detailed auroral structures. Here we report measurements of the radio emissions, which, along with high-resolution images of Saturn's ultraviolet auroral emissions, suggest that although there are differences in the global morphology of the aurorae, Saturn's radio emissions exhibit an Earth-like correspondence between bright auroral features and the radio emissions. This demonstrates the universality of the mechanism that results in emissions near the electron cyclotron frequency narrowly beamed at large angles to the magnetic field.

  18. Research and Development. Laboratory Activities.

    ERIC Educational Resources Information Center

    Gallaway, Ann, Ed.

    Research and Development is a laboratory-oriented course that includes the appropriate common essential elements for industrial technology education plus concepts and skills related to research and development. This guide provides teachers of the course with learning activities for secondary students. Introductory materials include an…

  19. Integral probability of auroral electron flux events from SSJ/4 DMSP F9 electron measurements. Interim report

    SciTech Connect

    Hardy, D.A.; Bounar, K.H.

    1992-05-18

    A study has been completed to determine the probability of observing different levels of auroral electron precipitation both within fixed spatial elements in magnetic local time and corrected geomagnetic latitude, and within spatial elements when the magnetic local time is fixed but the latitude range can be varied. The auroral electron precipitation probability is defined for a series of thresholds in electron average energy and electron energy flux as a function of geomagnetic activity. The study provides the capability to determine the probability of observation of an auroral electron precipitation event for any specified threshold in average energy, energy flux, and level of geomagnetic activity for any location in the auroral region or for any line of sight through the auroral region. The input for the study is one year of data from the SSJ/4 electron and proton spectrometer flown on the F9 satellite of the Defense Meteorological Satellite Program (DMSP) comprising approximately 10, 141 hemispheric passes through the auroral region. The binning technique used to determine these probabilities is presented and some results are discussed. The operation of the software package to display the probability results is described. Defense Meteorological Satellite Program (DMSP), Aurora, Precipitating electrons, Geomagnetic Kp index, Integral probability.

  20. Equatorward and poleward expansion of the auroras during auroral substorms

    NASA Technical Reports Server (NTRS)

    Nakamura, Rumi; Oguti, Takasi; Yamamoto, Tatsundo; Kokubun, Susumu

    1993-01-01

    The formation of the auroral bulge is investigated on the basis of all-sky TV auroral data with high spatial and temporal resolution. Ways in which the discrete auroral structures within the poleward expanding bulge develop systematically toward the west, the east, and also equatorward from a localized breakup region are shown. Auroral structure at the western end of the bulge (a surge) develops with clockwise rotation as viewed along the magnetic field direction. At the eastern part of the bulge, thin auroral features propagate eastward from the breakup region. Around the central meridian of the bulge, auroral features expand equatorward and become north-south aligned (the N-S aurora). The N-S aurora and the eastward propagating aurora develop into diffuse and pulsating aurora after the expansion. It is suggested that these discrete auroral structures in the bulge develop along the plasma streamlines in a localized distorted two-cell equipotential distribution.

  1. Particle Simulation of Auroral Double Layers

    DTIC Science & Technology

    1992-06-01

    exist parallel to the earth’s magnetic field [31, p. 99ffl and a source of energy must be available to drive Figure 1.1: A woodcut by Fridtjof Nansen ... Nansen depicts himself strolling on the ice under a triple curtain-like form of the aurora; the auroral arcs. (From Nansen’s Nord I Takeheunen, 1911

  2. Numerical and laboratory simulations of auroral acceleration

    SciTech Connect

    Gunell, H.; De Keyser, J.; Mann, I.

    2013-10-15

    The existence of parallel electric fields is an essential ingredient of auroral physics, leading to the acceleration of particles that give rise to the auroral displays. An auroral flux tube is modelled using electrostatic Vlasov simulations, and the results are compared to simulations of a proposed laboratory device that is meant for studies of the plasma physical processes that occur on auroral field lines. The hot magnetospheric plasma is represented by a gas discharge plasma source in the laboratory device, and the cold plasma mimicking the ionospheric plasma is generated by a Q-machine source. In both systems, double layers form with plasma density gradients concentrated on their high potential sides. The systems differ regarding the properties of ion acoustic waves that are heavily damped in the magnetosphere, where the ion population is hot, but weakly damped in the laboratory, where the discharge ions are cold. Ion waves are excited by the ion beam that is created by acceleration in the double layer in both systems. The efficiency of this beam-plasma interaction depends on the acceleration voltage. For voltages where the interaction is less efficient, the laboratory experiment is more space-like.

  3. Geophysicochemical model of an ionospheric auroral gyroscope

    NASA Astrophysics Data System (ADS)

    Serban, Andreea I.; Geicu, Ovidiu I.; Serban, Florea

    2016-01-01

    This study presents a geophysicochemical model of an ionospheric auroral gyroscope. The gyroscopic effect occurs due to the electromagnetic interaction in Earth's polar regions between two types of vertical cavity auroras: the herpolhodic cone (proton cavity aurora), operating in the cusp polar region, and two polhodic cones (an electronic cone and a protonic cone), operating in the aurora region. The ratio between the angular speeds of the herpolhodic and polhodic cones is established by the angle between Earth's rotational axis and the geomagnetic dipole axis. We have developed a theory of the ionospheric auroral gyroscope as a kinematic part of the terrestrial magnetosphere and ionosphere that enables a unified explanation of important macroscopic phenomena that occur at this level. Accordingly, we have explained the oval shape of the polar auroras, Schumann resonances, geomagnetic micropulsation excitation, and the structuring of Earth's areas of radiation. The terrestrial gravitomagnetic field and dark matter are implicated in the initiation and behavior of the auroral ionospheric gyroscope, both of which provide stability and accuracy. Viewed in a wider context, the ionospheric auroral gyroscope theory could offer a way to experimentally investigate dark matter on Earth. Furthermore, it may have a potential value as a predictive tool, providing information about the large earthquakes and Earth's phenomena.

  4. Multi-Camera Reconstruction of Fine Scale High Speed Auroral Dynamics

    NASA Astrophysics Data System (ADS)

    Hirsch, M.; Semeter, J. L.; Zettergren, M. D.; Dahlgren, H.; Goenka, C.; Akbari, H.

    2014-12-01

    The fine spatial structure of dispersive aurora is known to have ground-observable scales of less than 100 meters. The lifetime of prompt emissions is much less than 1 millisecond, and high-speed cameras have observed auroral forms with millisecond scale morphology. Satellite observations have corroborated these spatial and temporal findings. Satellite observation platforms give a very valuable yet passing glance at the auroral region and the precipitation driving the aurora. To gain further insight into the fine structure of accelerated particles driven into the ionosphere, ground-based optical instruments staring at the same region of sky can capture the evolution of processes evolving on time scales from milliseconds to many hours, with continuous sample rates of 100Hz or more. Legacy auroral tomography systems have used baselines of hundreds of kilometers, capturing a "side view" of the field-aligned auroral structure. We show that short baseline (less than 10 km), high speed optical observations fill a measurement gap between legacy long baseline optical observations and incoherent scatter radar. The ill-conditioned inverse problem typical of auroral tomography, accentuated by short baseline optical ground stations is tackled with contemporary data inversion algorithms. We leverage the disruptive electron multiplying charge coupled device (EMCCD) imaging technology and solve the inverse problem via eigenfunctions obtained from a first-principles 1-D electron penetration ionospheric model. We present the latest analysis of observed auroral events from the Poker Flat Research Range near Fairbanks, Alaska. We discuss the system-level design and performance verification measures needed to ensure consistent performance for nightly multi-terabyte data acquisition synchronized between stations to better than 1 millisecond.

  5. In situ observations of medium frequency auroral radio emissions

    NASA Astrophysics Data System (ADS)

    Broughton, M.; Labelle, J. W.; Pfaff, R. F.; Parrot, M.; Yan, X.; Burchill, J. K.

    2013-12-01

    The auroral ionosphere is a region rich with plasma waves that can be studied both in space and on the ground. These waves may mediate energy exchange between particle populations and provide information about the local plasma properties and boundaries. Auroral medium frequency (MF) burst is an impulsive radio emission observed at ground-level from 1.3-4.5 MHz that is associated with local substorm onset. There have been two recent reports of impulsive, broadband, MF waves at high latitudes. Burchill and Pfaff [2005] reported observations from the FAST satellite of impulsive, broadband, MF and low frequency (LF) radio waves. Using data from the DEMETER satellite, Parrot et al. [2009] surveyed MF waves caused by lightning. This study did show a high-latitude population of MF waves. We investigate whether the waves observed by these two satellites are related to auroral MF burst. Using FAST satellite burst mode electric field data from high-latitude (> 60 degrees magnetic), low-altitude (< 1000 km) intervals of moderate to large geomagnetic activity (Kp > 3) from 1996-2002, we have found forty-four examples of impulsive MF waves, all of which are associated with impulsive LF waves. Although MF burst and the waves observed by FAST have similar spectral signatures, they have different magnetic local time dependencies, which suggests that they may be unrelated. A study of MF waves observed at high latitude by DEMETER is ongoing. In situ observations of MF burst could provide crucial information about this heretofore unexplained natural radio emission.

  6. Auroral ultraviolet darkening on the outer planets

    SciTech Connect

    Pryor, W.R.

    1989-01-01

    The Voyager 2 Photopolarimeter Subsystem (PPS) has made photometric observations of Jupiter at 2400 A and photometric and polarimetric observations of Saturn and Uranus at 2650 A. At these wavelengths the instrument is observing each planet's stratosphere and upper troposphere. The most striking features are that both poles of Jupiter and the observed northern pole of Saturn are very dark, while Uranus has a uniformly bright appearance. All three planets show evidence for a stratospheric haze. Simple vertically homogeneous multiple scattering models are used to characterize these stratospheric hazes. Aurores occur at high latitudes on Jupiter and Saturn and at low latitudes on Uranus. The asymmetric polar darkening on Jupiter seen by PPS is roughly matched by the asymmetry in the auroral zones. Historical data suggest that the haze asymmetry is persistent. The dark north polar cap seen by PPS at Saturn is small and close to the pole, which corresponds to the small auroral zone close to the pole. A model is examined which attributes the darkening to auroral bombardment initiating methane chemistry that makes dark hydrocarbon particles. Possible chemical pathways are discussed, and mass balance calculations are presented for Jupiter, Saturn, and Uranus. The model is quantitatively plausible for Jupiter and Saturn. The lack of localized darkening on Uranus can be explained in this model by noting that weak vertical mixing and methane condensation near the 1-bar level lead to negligible methane abundances at auroral altitudes. The auroras must reach the methane for dark material to form. The thin haze that is seen on Uranus is ascribed to photochemical processes. Voyager 2 will reach Neptune this year. Ground-based observers have reported vigorous vertical mixing and large amounts of stratospheric methane there.

  7. Synoptical Auroral Ovals: A Comparison study with TIMED/GUVI Observations

    NASA Astrophysics Data System (ADS)

    Liou, K.; Paxton, L.; Zhang, Y.

    2007-12-01

    Whether the aurora Australis is a mirror image of its northern hemispheric counterpart is a question that auroral physicists have been wanting to answer. Owing to geophysical constraints, especially the large offset between the location of the southern magnetic and southern geographic poles, there is a paucity of information about the aurora Australis. Comparisons of some instantansous global-scale northern and southern auroras acquired conjugately by Polar and IMAGE spacecraft recently have shown mixed results. In this study, we present data from a different source to provide insight into the global morphology and behavior of the auroral oval. Approximately 20,000 Earth's disk FUV images acquired from the Global Ultraviolet Imager (GUVI) on-board NASA's Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite between February 2002 and February 2006 are processed and analyzed. Synoptic auroral distributions for the northern and southern ovals are derived. Our study result reveals that the statistical oval is nearly hemispherically symmetric (within ±80%). Several known features in the morphology of the aurora Borealis are also observed in the Southern Hemisphere: For instance, the auroral midday gap and the premidnight maximum. The hemispherical symmetry of the auroras deteriorates as the partition of solar illumination in the two hemisphere polar region becomes asymmetric. It is estimated that the solar illumination effect accounts for up to ~50% of the hemispheric asymmetry. We found evidence that suggests that the aurora is suppressed under sunlit conditions in the South just as it is in the North. We also found that the auroral energy flux increases monotonically with the increase of the solar zenith angle. These results suggest that ionospheric conductivity plays an active role in regulating magnetospheric energy deposition in the auroral zone.

  8. PC Index as a Means to Monitor Processes in the Auroral Zone

    NASA Astrophysics Data System (ADS)

    Troshichev, Oleg

    2016-07-01

    The PC index was introduced [Troshichev et al., 1988] to characterize the polar cap magnetic activity generated by the geoeffective interplanetary electric field. Results of recent studies [Troshichev and Janzhura, 2012; Troshichev and Sormakov, 2015] are strongly indicative of PC index as a proxy of the solar wind energy that entered into the magnetosphere. The PC index in this charge can be successfully used to monitor processes in the auroral zone: 1. PC index well correlates with intensity of the Region 1 field-aligned currents measured by SWARM satellites on the auroral oval poleward boundary. As it is known, the R1 field-aligned currents flow into ionosphere in the morning auroral oval and flow out of ionosphere in the evening oval. The R1 FAC intensity and, correspondingly, the PC value increase in tandem before the substorm sudden onset. 2. PC-index can be taken as Input Parameter in Empirical Auroral Precipitation Model "OVATION-prime" [Newell, 2009] instead of the coupling function dØMP/dt. Use of the 1-min PC index in the modified OVATION-PC model provides the much better timing of the auroral precipitation with allowance for actual state of the magnetosphere. 3. There is a strong correspondence between the behavior of PC and development of magnetic disturbances in the auroral zone: the magnetic substorms are preceded by the PC index growth, the substorm onsets are commonly associated with a sharp increase in the PC growth rate, the substorm occurrence reaches the maximum when PC exceeds the threshold value ~ 1.5±0.5 mV/m, the linear correlation between the PC and AL values is typical of all classes of substorms, irrespective of their power. There regularities provide possibility to nowcast the substorm development.

  9. Activities report of PTT Research

    NASA Astrophysics Data System (ADS)

    In the field of postal infrastructure research, activities were performed on postcode readers, radiolabels, and techniques of operations research and artificial intelligence. In the field of telecommunication, transportation, and information, research was made on multipurpose coding schemes, speech recognition, hypertext, a multimedia information server, security of electronic data interchange, document retrieval, improvement of the quality of user interfaces, domotics living support (techniques), and standardization of telecommunication prototcols. In the field of telecommunication infrastructure and provisions research, activities were performed on universal personal telecommunications, advanced broadband network technologies, coherent techniques, measurement of audio quality, near field facilities, local beam communication, local area networks, network security, coupling of broadband and narrowband integrated services digital networks, digital mapping, and standardization of protocols.

  10. Crowd-sourcing, Communicating, and Improving Auroral Science at the Speed of Social Media through Aurorasaurus.org

    NASA Astrophysics Data System (ADS)

    Patel, K.; MacDonald, E.; Case, N.; Hall, M.; Clayton, J.; Heavner, M.; Tapia, A.; Lalone, N.; McCloat, S.

    2015-12-01

    On March 17, 2015, a geomagnetic storm—the largest of the solar cycle to date— hit Earth and gave many sky watchers around the world a beautiful auroral display. People made thousands of aurora-related tweets and direct reports to Aurorasaurus.org, an interdisciplinary citizen science project that tracks auroras worldwide in real-time through social media and the project's apps and website. Through Aurorasaurus, researchers are converting these crowdsourced observations into valuable data points to help improve models of where aurora can be seen. In this presentation, we will highlight how the team communicates with the public during these global, sporadic events to help drive and retain participation for Aurorasaurus. We will highlight some of the co-produced scientific results and increased media interest following this event. Aurorasaurus uses mobile apps, blogging, and a volunteer scientist network to reach out to aurora enthusiasts to engage in the project. Real-time tweets are voted on by other users to verify their accuracy and are pinned on a map located on aurorasaurus.org to help show the instantaneous, global auroral visibility. Since the project launched in October 2014, hundreds of users have documented the two largest geomagnetic storms of this solar cycle. In some cases, like for the St. Patrick's Day storm, users even reported seeing aurora in areas different than aurora models suggested. Online analytics indicate these events drive users to our page and many also share images with various interest groups on social media. While citizen scientists provide observations, Aurorasaurus gives back by providing tools to help the public see and understand the aurora. When people verify auroral sightings in a specific area, the project sends out alerts to nearby users of possible auroral visibility. Aurorasaurus team members around the world also help the public understand the intricacies of space weather and aurora science through blog articles

  11. Generation of poleward moving auroral forms (PMAFs) during periods of dayside auroral oval expansions/contractions and periods when the dayside auroral oval is expanded and stable

    NASA Astrophysics Data System (ADS)

    Fasel, G. J.; Flicker, J.; Sibeck, D. G.; Alyami, M.; Angelo, A.; Aylward, R. J.; Bender, S.; Christensen, M.; Kim, J.; Kristensen, H.; Orellana, Y.; Sahin, O.; Yoon, J.; Green, D.; Sigernes, F.; Lorentzen, D. A.

    2013-12-01

    The latitude of the equatorial edge of the dayside auroral oval has been shown to vary with the direction of the IMF Bz-component. The equatorward/poleward edge of the dayside auroral oval shifts equatorward/poleward when the IMF Bz-component is negative/positive [Burch, 1973; Akasofu, 1977; Horwitz and Akasofu, 1977; Sandholt et al., 1986, 1988]. Past studies have shown that poleward-moving auroral forms (PMAFs) are a common feature during equatorward expansions of the dayside auroral oval. Horwitz and Akasofu [1977] noted a one-to-one correspondence of luminous PMAFs associated with an equatorward expansion of the dayside auroral oval. During the southward turning of the IMF Bz-component the merging rate on the dayside increases [Newell and Meng, 1987] leading to the erosion of the dayside magnetopause. The field line merging process is thought to be most efficient when the interplanetary magnetic field (IMF) Bz-component turns southward. Both Vorobjev et al. [1975] and Horwitz and Akasofu [1977] attributed these PMAFs to magnetic flux being eroded away from the dayside magnetopause and transported antisunward. Dayside poleward-moving auroral forms are also observed during periods of an expanded and stable dayside auroral oval for both northern and southern hemisphere observations [Sandholt et al., 1986, 1989, 1990; Rairden and Mende, 1989; Mende et al., 1990]. Poleward-moving auroral forms have also been observed during some dayside oval contractions but have not been discussed much in the literature. This study examines the dayside auroral oval during periods of expansion, contraction, and during periods of an expanded and stable dayside auroral oval. This statistical study will provide the following results: number of poleward-moving auroral forms that are generated during dayside auroral oval expansions/contractions and during periods of a stable and expanded dayside auroral oval, the average initial and final elevation angle of the dayside auroral oval, time

  12. Observing the magnetosphere through auroral imaging.

    NASA Astrophysics Data System (ADS)

    Mende, S. B.

    2015-12-01

    Although the terrestrial aurora is often regarded as 2 dimensional projection of the 3 dimensional magnetosphere there are fundamental limitations in observing magnetospheric processes through their auroral footprints. It has been shown that most electron auroras are produced in the auroral acceleration region at lower altitudes (<2Re) in the last steps of processing the auroral particles. From FAST, IMAGE , Cluster and THEMIS data we can distinguish between four fundamentally different types of auroral acceleration regions. A primary task is to distinguish (1) the upward current, (2) downward current, (3) diffuse aurora and (4) Alfven wave accelerated types of auroral acceleration regions. Type (1) contains the "inverted V" type electron precipitation distinguishable by several keV mono-energetic electron spectra, and low number flux consistent with the source population in the plasma sheet. Our understanding of how these auroras relate to magnetospheric processes is still vague, probably associated with convection sheer. Alfven wave electron auroras (4) are of low average energy (<2 keV) high electron flux consistent with ionospheric electron source predominantly occurring during substorms, and they are generated by wave energy carried from the magnetosphere into the ionosphere, where it is converted into electron energy. These are most promising candidates for observing the footprints of source regions associated with reconnection sites or magnetospheric dB/dt events. Optical measuring techniques of electron energy use the atmosphere as a spectrometer, obtaining the penetration altitude as a proxy for energy, that can be obtained from atmospheric composition, quenching lifetime of the emitters, UV absorption pass-length of O2 to the source or the local atmospheric temperature. Precipitating protons are usually an order of magnitude more energetic and less affected by fields in the low altitude auroral acceleration region. Energetic proton precipitation is a more

  13. Observations of amplitude saturation in ELF/VLF wave generation by modulated HF heating of the auroral electrojet

    NASA Astrophysics Data System (ADS)

    Moore, R. C.; Inan, U. S.; Bell, T. F.

    2006-06-01

    We present detailed observations of the onset of amplitude saturation in ELF/VLF waves generated via modulated HF heating of naturally-forming, large-scale current systems, such as the auroral electrojet. Broadband ELF/VLF measurements at a ground-based receiver located near the High-Frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska, exhibit variations in signal amplitude which are qualitatively consistent with a hard-limiting approximation of the saturation process. A method to approximate the saturation curve as a function of HF power from experimental data is presented, and the results indicate that a ~5-10% reduction in generated ELF signal amplitude is typical at the maximum radiated HF power level (771 kW) for modulation frequencies between 1225 Hz and 3365 Hz. For HF transmissions using sinusoidal amplitude modulation, the saturation dominantly affects the second harmonic of the generated ELF/VLF signal, with amplitudes on average 16% lower than expected at the maximum HF power level.

  14. Harmonic H sup + gyrofrequency structures in auroral hiss observed by high-altitude auroral sounding rockets

    SciTech Connect

    Kintner, P.M.; Vago, J. ); Scales, W. ); Yau, A.; Whalen, B. ); Arnoldy, R. ); Moore, T. )

    1991-06-01

    Two recent sounding rocket experiments have yielded VLF wave data with spectral structures ordered by the hydrogen gyrofrequency. The spectral structures occur near and above the lower hybrid frequency in association with auroral hiss. These structures are observed within and near regions of auroral electron precipitation and transverse ion acceleration. They are accompanied by auroral hiss but are anticorrelated with spectral peaks at the lower hybrid frequency. They are typically found above 500 km altitude, have no measureable magnetic component, and are at least occasionally short wavelength (k{rho}{sub i}{ge}1). Because the spectral structures appear to be electrostatic, are ordered by the hydrogen gyrofrequency, and are short wavelength, the authors interpret the structures as modes which connect the lower hybrid mode with the hydrogen Bernstein modes. A study of the plasma wave mode structure in the vicinity of the lower hybrid frequency is presented to substantiate this interpretation. The results imply that these waves are a common feature of the auroral zone ionosphere above 500 km altitude and exist any time that auroral hiss exists. The absence of previous satellite abservations of this phenomenon can be explained by Doppler broadening.

  15. Statistics of auroral hiss and relationship to auroral boundaries and upward current regions

    NASA Astrophysics Data System (ADS)

    Spasojevic, M.

    2016-08-01

    An 8 year database of VLF auroral hiss observations from South Pole station (invariant latitude of -74° with magnetic local time (MLT) = UT -3.5 h) is analyzed. There are three peaks in hiss occurrence as a function of MLT in the evening sector (19-23 MLT), afternoon sector (13-17 MLT), and morning sector (7-11 MLT). The geomagnetic and interplanetary magnetic field (IMF) drivers of hiss are examined in the three MLT sectors, and the results are interpreted using an empirical model of auroral boundaries and an empirical model of field-aligned current patterns. Auroral hiss on the dayside occurs when the auroral oval is centered near the latitude of the station, and in the afternoon sector higher disturbance levels are required. The afternoon sector favors positive By when Bz is positive and negative By when Bz is strongly negative, while the morning sector favors the complementary conditions. In each case the preference for hiss occurrence follows the pattern of upward field-aligned currents, and hiss is more likely in the configuration where the peak in the upward current is closer to the latitude of the station. IMF By does not play a role on the nightside where hiss is most likely to occur during moderately weak driving conditions as higher disturbance levels are expected to move the auroral oval and upward current systems to latitudes well equatorward of South Pole.

  16. Harmonic H(+) gyrofrequency structures in auroral hiss observed by high-altitude auroral sounding rockets

    NASA Technical Reports Server (NTRS)

    Kintner, P. M.; Vago, J.; Scales, W.; Yau, A.; Whalen, B.; Arnoldy, R.; Moore, T.

    1991-01-01

    Two recent sounding rocket experiments have yielded VLF wave data with spectral structures ordered by the hydrogen gyrofrequency. The spectral structures occur near and above the lower hybrid frequency in association with auroral hiss. These structures are observed within and near regions of auroral electron precipitation and transverse ion acceleration. They are accompanied by auroral hiss but are anticorrelated with spectral peaks at the lower hybrid frequency. They are typically found above 500 km altitude, have no measurable magnetic component, and are at least occasionally short wavelength. Because the spectral structures appear to be electrostatic, are ordered by the hydrogen gyrofrequency, and are short wavelength, the structures are interpreted as modes which connect the lower hybrid mode with the hydrogen Bernstein modes. A study of the plasma wave mode structure in the vicinity of the lower hybrid frequency is presented to substantiate this interpretation. These results imply that these waves are a common feature of the auroral zone ionsphere above 500 km altitude and exist any time that auroral hiss exists. The absence of previous satellite observations of this phenomenon can be explained by Doppler broadening.

  17. A numerical simulation of auroral ionospheric electrodynamics

    NASA Technical Reports Server (NTRS)

    Mallinckrodt, A. J.

    1985-01-01

    A computer simulation of auroral ionospheric electrodynamics in the altitude range 80 to 250 km has been developed. The routine will either simulate typical electron precipitation profiles or accept observed data. Using a model background ionosphere, ion production rates are calculated from which equilibrium electron densities and the Hall and Pedersen conductivities may be determined. With the specification of suitable boundary conditions, the entire three-dimensional current system and electric field may be calculated within the simulation region. The results of the application of the routine to a typical inverted-V precipitation profile are demonstrated. The routine is used to explore the observed anticorrelation between electric field magnitude and peak energy in the precipitating electron spectrum of an auroral arc.

  18. Auroral meridian scanning photometer calibration using Jupiter

    NASA Astrophysics Data System (ADS)

    Jackel, Brian J.; Unick, Craig; Creutzberg, Fokke; Baker, Greg; Davis, Eric; Donovan, Eric F.; Connors, Martin; Wilson, Cody; Little, Jarrett; Greffen, M.; McGuffin, Neil

    2016-10-01

    Observations of astronomical sources provide information that can significantly enhance the utility of auroral data for scientific studies. This report presents results obtained by using Jupiter for field cross calibration of four multispectral auroral meridian scanning photometers during the 2011-2015 Northern Hemisphere winters. Seasonal average optical field-of-view and local orientation estimates are obtained with uncertainties of 0.01 and 0.1°, respectively. Estimates of absolute sensitivity are repeatable to roughly 5 % from one month to the next, while the relative response between different wavelength channels is stable to better than 1 %. Astronomical field calibrations and darkroom calibration differences are on the order of 10 %. Atmospheric variability is the primary source of uncertainty; this may be reduced with complementary data from co-located instruments.

  19. Auroral plasma acceleration processes at Mars

    NASA Astrophysics Data System (ADS)

    Lundin, R.; Barabash, S.; Winningham, D.

    2012-09-01

    Following the first Mars Express (MEX) findings of auroral plasma acceleration above Martian magnetic anomalies[1, 2], a more detailed analysis is carried out regarding the physical processes that leads to plasma acceleration, and how they connect to the dynamo-, and energy source regions. The ultimate energy source for Martian plasma acceleration is the solar wind. The question is, by what mechanisms is solar wind energy and momentum transferred into the magnetic flux tubes that connect to Martian magnetic anomalies? What are the key plasma acceleration processes that lead to aurora and the associated ionospheric plasma outflow from Mars? The experimental setup on MEX limits our capability to carry out "auroral physics" at Mars. However, with knowledge acquired from the Earth, we may draw some analogies with terrestrial auroral physics. Using the limited data set available, consisting of primarily ASPERA and MARSIS data, an interesting picture of aurora at Mars emerges. There are some strong similarities between accelerated/heated electrons and ions in the nightside high altitude region above Mars and the electron/ion acceleration above Terrestrial discrete aurora. Nearly monoenergetic downgoing electrons are observed in conjunction with nearly monoenergetic upgoing ions. Monoenergetic counterstreaming ions and electrons is the signature of plasma acceleration in quasi-static electric fields. However, compared to the Earth's aurora, with auroral process guided by a dipole field, aurora at Mars is expected to form complex patterns in the multipole environment governed by the Martian crustal magnetic field regions. Moreover, temporal/spatial scales are different at Mars. It is therefore of interest to mention another common characteristics that exist for Earth and Mars, plasma acceleration by waves. Low-frequency, Alfvén, waves is a very powerful means of plasma acceleration in the Earth's magnetosphere. Low-frequency waves associated with plasma acceleration

  20. Auroral Simulation Studies. HAES Report No. 6

    DTIC Science & Technology

    1975-04-22

    an important source of 5577 emission in- the aurora. Intense auroral bombardment over a period of 4 minutes is found to result in negligible...hereby gratefully acknOwledged. I K4 A 11 7~. 4 - 1i PREFACE The High Altitude Effects Simulation (IIABS) Program sponsored by the Defense Nuclear Agency...and Conclusions 93 02( A) EMISSION 95 4 TABLE OF CONTENTS (Continued) PAGE !ECTION 3 STUDIES RELATED TO LWIR PRODUCTION AND TO EUV EFFECTS IN THE

  1. Investigation of electrical currents in the auroral ionosphere

    NASA Technical Reports Server (NTRS)

    Arnoldy, R. L.

    1978-01-01

    Two papers are presented on the investigation of electrical currents in the auroral ionosphere: (1) The Relationship Between Field-Aligned Current Carried by Suprathermal Electrons, and the Auroral Arc; and (2) Ionospheric Electrical Currents in the Late Evening Plasma Flow Reversal. In the first paper (1), data from four auroral sounding rockets, which directly measured field-aligned currents with partical detectors, are presented. In the second paper (2), data are presented for an instrumented sounding rocket that was launched from Andoya, Norway in January 1977, in the late evening auroral oval.

  2. Study of sub-auroral radio emissions observed by ICE experiment onboard DEMETER satellite

    NASA Astrophysics Data System (ADS)

    Boudjada, M. Y.; Galopeau, P. H. M.; Mogilevski, M. M.; Sawas, S.; Blecki, J.; Berthelier, J. J.; Voller, W.

    2012-04-01

    We report on the terrestrial kilometric and hectometric radio emissions recorded by the DEMETER/ICE (Instrument Champ Electrique) experiment. This instrument measures the electric field components of electromagnetic and electrostatic waves in the frequency range from DC to 3.25 MHz. Despite the limited satellite invariant latitude (data acquisition below about 65°), specific events have been observed, close to the sub-auroral region, in the frequency range from 100 kHz to about 1 MHz. This range covers the well-known auroral kilometric radiation (AKR), the terrestrial kilometric continuum, and the sub-auroral terrestrial emission at higher frequency up to 3 MHz. The high spectral capability of the experiment leads us to distinguish between the bursty and the continuum emissions. Selected events have been found to principally occur in the late evening and early morning sectors of the magnetosphere (22 MLT - 02 MLT) but others have been observed on the dayside. Our first results are compared to previous radio observations performed on board INTERBALL-1 (Kuril'chik et al, Cosmic Research, 43, 2005) and GEOTAIL (Hashimoto et al., JGR, 104, 1999) satellites. We also discuss the common and different features of the Earth and Jovian radio emissions. We emphasis on the observational parameters: the occurrence probability, the emission beam and the spectral emission types. We show that the physical interpretation of the auroral phenomena needs a good knowledge of the geometric configuration of the source and observer and the reception system (antenna beam and receivers).

  3. Characteristics of 630nm auroral polarization observed at Pokar Flat, Alaska

    NASA Astrophysics Data System (ADS)

    Shimpei, T.; Kagitani, M.; Sakanoi, T.; Hampton, D. L.

    2014-12-01

    We report the result of OI 630 nm auroral polarization observation at Poker Flat Research Range (Glat=65.12N, Glon=147.43W, Mlat=65.72N) during the period from December 2013 to April 2014. OI 630nm auroral emission is theoretically expected to show linear polarization with degrees up to 17% [Bommier et al., 2011]. The important point is that, the degree of linear polarization depends on energy and velocity anisotropy of precipitating electrons [Fujimoto et al., 1997]. Recent observation data also showed that 630nm auroral emission related to polar rain at high-latitudes linear polarization parallel to field with degrees of 2-7%[Lilensten et al., 2013]. However, these past measurements were limited in the polar cap region and its polarization characteristics are not clear. To examine auroral polarization with an accuracy of 1% polarization degree, we developed an imaging spectrograph which can measure auroral polarization in the wide field-of-view of 130 deg covering the wavelength range from 420 nm to 680 nm (resolution 2 nm). This new instrument enables us to obtain the linear polarization degrees at 557.7 nm and 630 nm auroral emissions simultaneously. Here, we can regard 557.7 nm aurora as a standard polarization light source because it does not produce polarization theoretically. We installed the spectrograph at Poker Flat Research Range and carried out precise calibration to estimate artificial polarization which is produced inside the optical system using an LED light source with a linear polarizer every 3 hours on five nights in December 2013. Since then, automatic operation was continuously carried every night out till the beginning of April 2014.We obtained the linear polarization of 630 nm aurora with degree of 5% showing elevation angle dependence. On the other hand, we unexpectedly measured the polarization of 557.7 nm emission which shows similar polarization property as 630 nm. We are considering two possibilities to interpret the results as follows

  4. Coordinated analysis of various auroral measurements made during NASA's 1968 and 1969 airborne auroral expeditions

    NASA Technical Reports Server (NTRS)

    Sivjee, G. G.

    1976-01-01

    Auroral optical measurements made aboard NASA's CV 990 were analyzed. The measurements analyzed form a small part of extensive spectroscopic, photometric and photographic data gathered during the 1968 and 1969 Airborne Auroral Expeditions. Simultaneous particle measurements from ESRO IA satellite were used in the analysis. Information about magnetospheric boundaries, interaction between magnetosheath particles and the terrestrial ionosphere, the polar bulge in helium abundance and excitation mechanisms of the triplet state of atmospheric N2 in auroras was obtained. Further analysis of the data is required to elucidate the relation between 3466 and 5200 A emissions of NI and the excitation of 3726-3729 A emissions from atomic oxygen ions in auroras.

  5. Spacecraft Charging and Auroral Boundary Predictions in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.

    2016-01-01

    Auroral charging of spacecraft is an important class of space weather impacts on technological systems in low Earth orbit. In order for space weather models to accurately specify auroral charging environments, they must provide the appropriate plasma environment characteristics responsible for charging. Improvements in operational space weather prediction capabilities relevant to charging must be tested against charging observations.

  6. Anomalous dc resistivity and double layers in the auroral ionosphere

    SciTech Connect

    Kindel, J.M.; Barnes, C.; Forslund, D.W.

    1980-01-01

    There are at least four candidate instabilities which might account for anomalous dc rereresistivity in the auroral ionosphere. These are: the ion-acoustic instability, the Buneman instability, the ion-cyclotron instability and double layers. Results are reported of computer simulations of these four instabilities which suggest that double layers are most likely to be responsible for sistivity in the auroral zone.

  7. Solar Wind Structure Sources and Periodicites of Auroral Electron Power Over the Three Solar Cycles

    DTIC Science & Technology

    2009-01-01

    Gonzalez. W.D.. Gonzalez, A.L.C., Tsurutani, B.T., 1990. Dual-peak cycle distribution of intense geomagnetic storms . Planetary and Space Sciences 38, 181...1995-1999. © 2008 Elsevier Ltd. All rights reserved. 1. Introduction v One of the methods of estimating auroral activity is to derive the...geomagnetic activity indices of Kp and ap, where ap is a linearization of the Kp index . Emery et al. (2008) showed that the cross-correlations of daily

  8. Electron Precipitation Associated with Small-Scale Auroral Structures

    NASA Astrophysics Data System (ADS)

    Michell, R.; Samara, M.; Grubbs, G. A., II; Hampton, D. L.; Bonnell, J. W.; Ogasawara, K.

    2014-12-01

    We present results from the Ground-to-Rocket Electrons Electrodynamics Correlative Experiment (GREECE) sounding rocket mission, where we combined high-resolution ground-based auroral imaging with high time-resolution precipitating electron measurements. The GREECE payload successfully launched from Poker Flat, Alaska on 03 March 2014 and reached an apogee of approximately 335 km. The narrow field-of-view auroral imaging was taken from Venetie, AK, which is directly under apogee. This enabled the small-scale auroral features at the magnetic footpoint of the rocket payload to be imaged in detail. The electron precipitation was measured with the Acute Precipitating Electron Spectrometer (APES) onboard the payload. Features in the electron data are matched up with their corresponding auroral structures and boundaries, enabling measurement of the exact electron distributions responsible for the specific small-scale auroral features. These electron distributions will then be used to infer what the potential electron acceleration processes were.

  9. Auroral Charging of the International Space Station

    NASA Astrophysics Data System (ADS)

    Minow, J. I.; Chandler, M. O.; Wright, K. H.

    2011-12-01

    Electrostatic potential variations of the International Space Station (ISS) relative to the space plasma environment are dominated by biased surfaces of the 160 volt photovoltaic power system with the low Earth orbit plasma environment in sunlight and inductive potential variations across the ISS structure generated by motion of the large vehicle across the geomagnetic field. We have seen little or no evidence to date of daytime ISS potential variations due to space weather events that generate short term variations in ionospheric plasma density or temperature since the primary result of geomagnetic storms at ISS altitudes is depletion of plasma density which suppresses charging levels due to the photovoltaic array controlled current collection process. Auroral charging is also a source of potential variations because the 51.6 degree orbital inclination of ISS takes the vehicle to sufficiently high magnetic latitudes to encounter precipitating electrons during geomagnetic storms. We present observations of transient ISS floating potential, plasma density, and electron temperature variations obtained from the Floating Potential Measurement Unit (FPMU) suite of plasma instruments on board the ISS which exhibit characteristics consistent with auroral charging. The events occur primarily at night when the solar arrays are unbiased and cannot therefore be due to solar array current collection. ISS potential decreases to more negative values during the events indicating electron current collection and the events are always observed at the highest latitudes along the ISS trajectory. Comparison of the events with integral >30 keV electron flux measurements from NOAA TIROS spacecraft demonstrate they occur within regions of precipitating electron flux at levels consistent with the energetic electron thresholds reported for onset of auroral charging of the DMSP and Freja satellites. Properties of the charging events similar to those reported for DSMP and Freja satellites

  10. Atmospheric spreading of protons in auroral arcs

    NASA Technical Reports Server (NTRS)

    Iglesias, G. E.; Vondrak, R. R.

    1974-01-01

    A model is developed to calculate the effect of atmospheric spreading on the flux and angular distribution of protons in homogeneous auroral arcs. An expression is derived that indicates the angular distribution in the atmosphere as a function of distance from arc center, neutral scale height, arc width, and initial angular distribution. The results of the model agree favorably with those based on Monte-Carlo calculations. From these results the enhancement factors needed to compute the original proton current above the atmosphere are obtained. A technique is indicated for determining the incident angular distribution from rocket-based measurements of the arc width and angular distribution.

  11. Geotail Measurements Compared with the Motions of High-Latitude Auroral Boundaries during Two Substorms

    NASA Technical Reports Server (NTRS)

    Maynard, N. C.; Burke, W. J.; Erickson, G. M.; Nakamura, M.; Mukai, T.; Kokubun, S.; Yamamoto, T.; Jacobsen, B.; Egeland, A.; Samson, J. C.; Weimer, D. R.; Reeves, G. D.; Luhr, H.

    1997-01-01

    Geotail plasma and field measurements at -95 R(sub E) are compared with extensive ground-based, near-Earth, and geosynchronous measurements to study relationships between auroral activity and magnetotail dynamics during the expansion phases of two substorms. The studied intervals are representative of intermittent, moderate activity. The behavior of the aurora and the observed effects at Geotail for both events are harmonized by the concept of the activation of near-Earth X lines (NEXL) after substorm onsets, with subsequent discharges of one or more plasmoids down the magnetotail. The plasmoids must be viewed as three-dimensional structures which are spatially limited in the dawn-dusk direction. Also, reconnection at the NEXL must proceed at variable rates on closed magnetic field lines for significant times before beginning to reconnect lobe flux. This implies that the plasma sheet in the near-Earth magnetotail is relatively thick in comparison with an embedded current sheet and that both the NEXL and distant X line can be active simultaneously. Until reconnection at the NEXL engages lobe flux, the distant X line maintains control of the poleward auroral boundary. If the NEXL remains active after reaching the lobe, the auroral boundary can move poleward explosively. The dynamics of high-latitude aurora in the midnight region thus provides a means for monitoring these processes and indicating when significant lobe flux reconnects at the NEXL.

  12. In situ analysis of measurements of auroral dynamics and structure

    NASA Astrophysics Data System (ADS)

    Mella, Meghan R.

    Two auroral sounding rocket case studies, one in the dayside and one in the nightside, explore aspects of poleward boundary aurora. The nightside sounding rocket, Cascades-2 was launched on 20 March 2009 at 11:04:00 UT from the Poker Flat Research Range in Alaska, and flew across a series of poleward boundary intensifications (PBIs). Each of the crossings have fundamentally different in situ electron energy and pitch angle structure, and different ground optics images of visible aurora. The different particle distributions show signatures of both a quasistatic acceleration mechanism and an Alfvenic acceleration mechanism, as well as combinations of both. The Cascades-2 experiment is the first sounding rocket observation of a PBI sequence, enabling a detailed investigation of the electron signatures and optical aurora associated with various stages of a PBI sequence as it evolves from an Alfvenic to a more quasistatic structure. The dayside sounding rocket, Scifer-2 was launched on 18 January 2008 at 7:30 UT from the Andoya Rocket Range in Andenes, Norway. It flew northward through the cleft region during a Poleward Moving Auroral Form (PMAF) event. Both the dayside and nightside flights observe dispersed, precipitating ions, each of a different nature. The dispersion signatures are dependent on, among other things, the MLT sector, altitude, source region, and precipitation mechanism. It is found that small changes in the shape of the dispersion have a large influence on whether the precipitation was localized or extended over a range of altitudes. It is also found that a single Maxwellian source will not replicate the data, but rather, a sum of Maxwellians of different temperature, similar to a Kappa distribution, most closely reproduces the data. The various particle signatures are used to argue that both events have similar magnetospheric drivers, that is, Bursty Bulk Flows in the magnetotail.

  13. E and F region study of the evening sector auroral oval - A Chatanika/Dynamics Explorer 2/NOAA 6 comparison

    NASA Technical Reports Server (NTRS)

    Senior, C.; Sharber, J. R.; Winningham, J. D.; De La Beaujardiere, O.; Heelis, R. A.; Evans, D. S.; Sugiura, M.; Hoegy, W. R.

    1987-01-01

    Simultaneous data from the Chatanika radar and the DE 2 and NOAA 6 satellites are used to study the typical behavior of the winter evening-sector auroral plasma during moderate and steady magnetic activity. The equatorward edge of the auroral E layer, of the region 2 field-aligned currents, and of the region of intense convection are colocated. The auroral E layer extends several degrees south of the equatorward edge of the keV electron precipitation from the CPS. Although the main trough and ionization channel are embedded in a region of intense electric field where the plasma flows sunward at high speed, the flux tubes associated with these two features have different time histories. The midlatitude trough is located south of the region of electron precipitation, above a proton aurora. The ionization channel marks the poleward edge of the main trough and is colocated with the equatorward boundary of the electron precipitation from the central plasma sheet.

  14. Ion heating in an auroral potential structure

    NASA Astrophysics Data System (ADS)

    Anastasiadis, A.; Daglis, I. A.; Tsironis, C.

    2004-06-01

    We investigate the interaction of O+ ions with a one-dimensional potential well, using Hamiltonian formulation. Heating of plasma originating in the terrestrial ionosphere plays a catalytic role in solar-driven magnetic storms, which dissipate energy globally within the magnetosphere of the earth. An interesting candidate for ionospheric plasma heating is a potential well located at auroral arcs in the high-latitude magnetosphere. We consider a potential with an exponential form, having a characteristic length Lx. The oxygen ions drift towards the auroral arc in the presence of a constant magnetic field Bz and a constant electric field Ey. The orbits of individual ions for different initial conditions - phase angle and kinetic energy - are traced. Our results show that, depending upon the initial conditions, test particles can be either accelerated or decelerated. Furthermore, we perform a parametric study for the interactions of mono-energetic and Maxwellian type of initial ion distribution - using random phase angle injection of the particles - with respect to our main model parameter, the characteristic length of the potential Lx. We conclude that for characteristic lengths comparable to twice the ion gyroradius, the O+ population is accelerated.

  15. DMSP Spacecraft Charging in Auroral Environments

    NASA Technical Reports Server (NTRS)

    Colson, Andrew; Minow, Joseph

    2011-01-01

    The Defense Meteorological Satellite Program (DMSP) spacecraft are a series of low-earth orbit (LEO) satellites whose mission is to observe the space environment using the precipitating energetic particle spectrometer (SSJ/4-5). DMSP satellites fly in a geosynchronous orbit at approx.840 km altitude which passes through Earth s ionosphere. The ionosphere is a region of partially ionized gas (plasma) formed by the photoionization of neutral atoms and molecules in the upper atmosphere of Earth. For satellites in LEO, such as DMSP, the plasma density is usually high and the main contributors to the currents to the spacecraft are the precipitating auroral electrons and ions from the magnetosphere as well as the cold plasma that constitutes the ionosphere. It is important to understand how the ionosphere and auroral electrons can accumulate surface charges on satellites because spacecraft charging has been the cause of a number of significant anomalies for on-board instrumentation on high altitude spacecraft. These range from limiting the sensitivity of measurements to instrument malfunction depending on the magnitude of the potential difference over the spacecraft surface. Interactive Data Language (IDL) software was developed to process SSJ/4-5 electron and ion data and to create a spectrogram of the particles number and energy fluxes. The purpose of this study is to identify DMSP spacecraft charging events and to present a preliminary statistical analysis. Nomenclature

  16. Cluster in the Auroral Acceleration Region

    NASA Technical Reports Server (NTRS)

    Pickett, Jolene S.; Fazakerley, Andrew N.; Marklund, Gorun; Dandouras, Iannis; Christopher, Ivar W.; Kistler, Lynn; Lucek, Elizabeth; Masson, Arnaud; Taylor, Matthew G.; Mutel, Robert L.; Santolik, Ondrej; Bell, Timothy F.; Fung, Shing; Pottelette, Raymond; Hanasz, Jan; Schreiber, Roman; Hull, Arthur J.

    2010-01-01

    Due to a fortuitous evolution of the Cluster orbit, the Cluster spacecraft penetrated for the first time in its mission the heart of Earth's auroral acceleration region (AAR) in December 2009 and January 2010. During this time a special AAR campaign was carried out by the various Cluster instrument teams with special support from ESA and NASA facilities. We present some of the first multi-spacecraft observations of the waves, particles and fields made during that campaign. The Cluster spacecraft configuration during these AAR passages was such that it allowed us to explore the differences in the signatures of waves, particles, and fields on the various spacecraft in ways not possible with single spacecraft. For example, one spacecraft was more poleward than the other three (C2), one was at higher altitude (C1), and one of them (0) followed another (C4) through the AAR on approximately the same track but delayed by three minutes. Their separations were generally on the order of a few thousand km or less and occasionally two of them were lying along the same magnetic field line. We will show some of the first analyses of the data obtained during the AAR campaign, where upward and downward current regions, and the waves specifically associated with those regions, as well as the auroral cavities, were observed similarly and differently on the various spacecraft, helping us to explore the spatial, as well as the temporal, aspects of processes occurring in the AAR.

  17. ISIS-II Scanning Auroral Photometer.

    PubMed

    Anger, C D; Fancott, T; McNally, J; Kerr, H S

    1973-08-01

    The ISIS-II dual wavelength scanning auroral photometer is designed to map the distribution of auroral emissions at 5577 A and 3914 A over the portion of the dark earth visible to the spacecraft. A combination of internal electronic scanning and the natural orbital and rotational motions of the spacecraft causes a dual wavelength photometer to be scanned systematically across the earth. The data will be reproduced directly in the form of separate pictures representing emissions at each wavelength, which will be used to study the large-scale distribution and morphology of auroras, to study the ratio of 3914-A and 5577-A emissions thought to depend upon the energies of exciting particles), and to compare with results from other instruments on board the spacecraft and on the ground. The Red Line Photometer experiment on the same spacecraft is described in an accompanying paper by Shepherd et al. [Appl. Opt. 12, 1767 (1973)]. The instrument can be thought of as the photometric equivalent of an all-sky color camera which will view the aurora from above instead of below and with a much wider vantage point unobstructed by cloud and haze. In one satellite pass, the instrument will be capable of surveying (in one hemisphere) the entire polar region in which auroras normally occur.

  18. Clean Coal Program Research Activities

    SciTech Connect

    Larry Baxter; Eric Eddings; Thomas Fletcher; Kerry Kelly; JoAnn Lighty; Ronald Pugmire; Adel Sarofim; Geoffrey Silcox; Phillip Smith; Jeremy Thornock; Jost Wendt; Kevin Whitty

    2009-03-31

    Although remarkable progress has been made in developing technologies for the clean and efficient utilization of coal, the biggest challenge in the utilization of coal is still the protection of the environment. Specifically, electric utilities face increasingly stringent restriction on the emissions of NO{sub x} and SO{sub x}, new mercury emission standards, and mounting pressure for the mitigation of CO{sub 2} emissions, an environmental challenge that is greater than any they have previously faced. The Utah Clean Coal Program addressed issues related to innovations for existing power plants including retrofit technologies for carbon capture and sequestration (CCS) or green field plants with CCS. The Program focused on the following areas: simulation, mercury control, oxycoal combustion, gasification, sequestration, chemical looping combustion, materials investigations and student research experiences. The goal of this program was to begin to integrate the experimental and simulation activities and to partner with NETL researchers to integrate the Program's results with those at NETL, using simulation as the vehicle for integration and innovation. The investigators also committed to training students in coal utilization technology tuned to the environmental constraints that we face in the future; to this end the Program supported approximately 12 graduate students toward the completion of their graduate degree in addition to numerous undergraduate students. With the increased importance of coal for energy independence, training of graduate and undergraduate students in the development of new technologies is critical.

  19. Constraining Substellar Magnetic Dynamos using Auroral Radio Emission

    NASA Astrophysics Data System (ADS)

    Kao, Melodie; Hallinan, Gregg; Pineda, J. Sebastian; Escala, Ivanna; Burgasser, Adam J.; Stevenson, David J.

    2017-01-01

    An important outstanding problem in dynamo theory is understanding how magnetic fields are generated and sustained in fully convective stellar objects. A number of models for possible dynamo mechanisms in this regime have been proposed but constraining data on magnetic field strengths and topologies across a wide range of mass, age, rotation rate, and temperature are sorely lacking, particularly in the brown dwarf regime. Detections of highly circularly polarized pulsed radio emission provide our only window into magnetic field measurements for objects in the ultracool brown dwarf regime. However, these detections are very rare; previous radio surveys encompassing ˜60 L6 or later targets have yielded only one detection. We have developed a selection strategy for biasing survey targets based on possible optical and infrared tracers of auroral activity. Using our selection strategy, we previously observed six late L and T dwarfs with the Jansky Very Large Array (VLA) and detected the presence of highly circularly polarized radio emission for five targets. Our initial detections at 4-8 GHz provided the most robust constraints on dynamo theory in this regime, confirming magnetic fields >2.5 kG. To further develop our understanding of magnetic fields in the ultracool brown dwarf mass regime bridging planets and stars, we present constraints on surface magnetic field strengths for two Y-dwarfs as well as higher frequency observations of the previously detected L/T dwarfs corresponding ~3.6 kG fields. By carefully comparing magnetic field measurements derived from auroral radio emission to measurements derived from Zeeman broadening and Zeeman Doppler imaging, we provide tentative evidence that the dynamo operating in this mass regime may be inconsistent with predicted values from currently in vogue models. This suggests that parameters beyond convective flux may influence magnetic field generation in brown dwarfs.

  20. Unusual rainbow and white rainbow: A new auroral candidate in oriental historical sources

    NASA Astrophysics Data System (ADS)

    Hayakawa, Hisashi; Isobe, Hiroaki; Davis Kawamura, Akito; Tamazawa, Harufumi; Miyahara, Hiroko; Kataoka, Ryuho

    2016-06-01

    Solar activity has been recorded as auroras or sunspots in various historical sources. These records are of great importance for investigating both long-term solar activities and extremely intense solar flares. According to previous studies, they were recorded as "vapor," "cloud," or "light," especially in oriental historical sources; however, this terminology has not been discussed adequately, and remains still quite vague. In this paper, we suggest the possibility of using "unusual rainbow" and "white rainbow" as candidates of historical auroras in oriental historical sources, and examine if this is probable. This discovery will help us to make more comprehensive historical auroral catalogues, and require us to add these terms to auroral candidates in oriental historical sources.

  1. Matching software practitioner needs to researcher activities

    NASA Technical Reports Server (NTRS)

    Feather, M. S.; Menzies, T.; Connelly, J. R.

    2003-01-01

    We present an approach to matching software practitioners' needs to software researchers' activities. It uses an accepted taxonomical software classfication scheme as intermediary, in terms of which practitioners express needs, and researchers express activities.

  2. On a possible connection between the longitudinally propagating near-Earth plasma sheet and auroral arc waves: A reexamination

    NASA Astrophysics Data System (ADS)

    Motoba, T.; Ohtani, S.; Donovan, E. F.; Angelopoulos, V.

    2015-01-01

    propagating low-frequency waves (or wavy structures) often occur in a localized region of the near-Earth plasma sheet and auroral arc immediately prior to auroral breakup. Although both are believed to be magnetospheric and ionospheric manifestations of a plasma sheet instability that may lead to substorm onset, the fundamental coupling processes behind their relationship are not yet understood. To address this question, we reexamined in detail a fortuitous conjunction event of prebreakup near-Earth plasma sheet and auroral arc waves, initially reported by Uritsky et al. (2009) using the Time History of Events and Macroscale Interactions during Substorms space-ground observations. The event exhibited a morphological one-to-one association between longitudinally propagating arc wave (LPAW) in the ionosphere and Pi2/Pc4 range wave activity in the plasma sheet. Our analysis revealed that (1) the LPAW was the periodic luminosity modulation of the growth phase arc by faint, diffuse, green line-dominated auroral patches propagating westward along/near the arc, rather than some type of small-scale arc structuring, such as auroral beads/rays/undulations; and (2) the plasma sheet wave, which had a diamagnetic nature, propagated duskward with accompanying coincident modulation of field-aligned fluxes of 0.1-30 keV electrons. These findings suggest that the LPAW was likely connected to the plasma sheet wave via modulated diffuse precipitation of hard plasma sheet electrons (> ~1 keV), not via filamentary field-aligned currents, as expected from the ballooning instability regime. Another potential implication is that such prebreakup low-frequency wave activity in the near-Earth plasma sheet is not necessarily guaranteed to initiate prebreakup auroral arc structuring.

  3. Dark auroral oval on saturn discovered in hubble space telescope ultraviolet images.

    PubMed

    Jaffel, L B; Leers, V; Sandel, B R

    1995-08-18

    Hubble Space Telescope ultraviolet images of Saturn obtained with the Faint Object Camera near 220 nanometers reveal a dark oval encircling the north magnetic pole of the planet. The opacity has an equivalent width of approximately 11 degrees in latitude and is centered around approximately 79 degrees N. The oval shape of the dark structure and its coincidence with the aurora detected by the Voyager Ultraviolet Spectrometer suggest that the aerosol formation is related to the auroral activity.

  4. Collisionless effects on the spectrum of secondary auroral electrons at low altitudes

    NASA Technical Reports Server (NTRS)

    Papadopoulos, K.; Rowland, H. L.

    1978-01-01

    A common feature of all rocket measurements of the differential flux of primary and secondary electrons under auroral activity is that between 30 and 85 eV, where the measurements overlap in energy, the electron flux data can be fitted by a certain power law. In the present paper, it is shown that the existence of plasma waves even in a region where they are nonresonant with the ambient particles can significantly modify the observed flux power law.

  5. Determining the source region of auroral emissions in the prenoon oval using coordinated Polar BEAR UV-imaging and DMSP particle measurements

    SciTech Connect

    Newell, P.T.; Meng, C.I. ); Huffman, R.E. )

    1992-08-01

    The Polar Beacon Experiment and Auroral Research (Polar BEAR) satellite included the capability for imaging the dayside auroral oval in full sunlight at several wavelengths. The authors compare particle observations from the DMSP F7 satellite during dayside auroral oval crossings with approximately simultaneous Polar BEAR 1,356-{angstrom} images to determine the magnetospheric source region of the dayside auroral oval. The source region is determined from the Defense Meteorological Satellite Program (DMSP) particle data, according to recent work concerning the classification and identification of precipitation source regions. The close DMSP/Polar BEAR coincidences all occur when the former satellite is located between 0945 and 1,000 MLT. The authors found instances of auroral arcs mapping to each of several different regions, including the boundary plasma sheet, the low-latitude boundary layer, and the plasma mantle. However, the results indicate that about half the time the most prominent auroral arcs are located at the interfaces between distinct plasma regions, at least at the local time studied here.

  6. Excitation of whistler waves by reflected auroral electrons

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Dillenburg, D.; Ziebell, L. F.; Freund, H. P.

    1983-01-01

    Excitation of electron waves and whistlers by reflected auroral electrons which possess a loss-cone distribution is investigated. Based on a given magnetic field and density model, the instability problem is studied over a broad region along the auroral field lines. This region covers altitudes ranging from one quarter of an earth radius to five earth radii. It is found that the growth rate is significant only in the region of low altitude, say below the source region of the auroral kilometric radiation. In the high altitude region the instability is insignificant either because of low refractive indices or because of small loss cone angles.

  7. Generation of auroral kilometric radiation in inhomogeneous magnetospheric plasma

    NASA Astrophysics Data System (ADS)

    Burinskaya, T. M.; Shevelev, M. M.

    2017-01-01

    The generation of auroral kilometric radiation in a narrow 3D plasma cavity, in which a weakly relativistic electron flow is propagated along the magnetic field against a low-density cold background plasma, is studied. The time dynamics of the propagation and intensification of waves are analyzed using geometric optics equations. The waves have different wave vector components and start from the cavity center at an altitude of about the Earth's radius at plasma parameters typical for the auroral zone at this altitude. It is shown that the global inhomogeneity of the Earth's magnetic field is of key importance in shaping the auroral kilometric radiation spectra.

  8. Relating practitioner needs to research activities

    NASA Technical Reports Server (NTRS)

    Feather, M. S.; Menzies, T.; Connelly, J. R.

    2003-01-01

    We present an approach to matching needs (practioner requirements) to solutions (researcher activities). A taxonomical classification scheme acts as intermediary between needs and activities. Expert practitioners exprss their needs in terms of this taxonomy. Researchers express their activities in the same terms. A decision support tool is used to assist in the combination and study of their expressions of needs and activities.

  9. OCLC Research: 2012 Activity Report

    ERIC Educational Resources Information Center

    OCLC Online Computer Library Center, Inc., 2013

    2013-01-01

    The mission of the Online Computer Library Center (OCLC) Research is to expand knowledge that advances OCLC's public purposes of furthering access to the world's information and reducing library costs. OCLC Research is dedicated to three roles: (1)To act as a community resource for shared research and development (R&D); (2) To provide advanced…

  10. Global Auroral Energy Deposition Compared with Magnetic Indices

    NASA Technical Reports Server (NTRS)

    Brittnacher, M. J.; Fillingim, M. O.; Elsen, R.; Parks, G. K.; Germany, G. A.; Spann, J. F., Jr.

    1997-01-01

    Measurement of the global rate of energy deposition in the ionosphere via auroral particle precipitation is one of the primary goals of the Polar UVI program and is an important component of the ISTP program. The instantaneous rate of energy deposition for the entire month of January 1997 has been calculated by applying models to the UVI images and is presented by Fillingim et al. in this session. Magnetic indices, such as Kp, AE, and Dst, which are sensitive to variations in magnetospheric current systems have been constructed from ground magnetometer measurements and employed as measures of activity. The systematic study of global energy deposition raises the possibility of constructing a global magnetospheric activity index explicitly based on particle precipitation to supplement magnetic indices derived from ground magnetometer measurements. The relationship between global magnetic activity as measured by these indices and the rate of total global energy loss due to precipitation is not known at present. We study the correlation of the traditional magnetic index of Kp for the month of January 1997 with the energy deposition derived from the UVI images. We address the question of whether the energy deposition through particle precipitation generally matches the Kp and AE indices, or the more exciting, but distinct, possibility that this particle-derived index may provide an somewhat independent measure of global magnetospheric activity that could supplement traditional magnetically-based activity indices.

  11. Small-scale auroral Arc deformations

    NASA Astrophysics Data System (ADS)

    Wagner, J. S.; Sydora, R. D.; Tajima, T.; Hallinan, T.; Lee, L. C.; Akasofu, S.-I.

    1983-10-01

    An auroral arc undergoes various types of deformations, such as curls, folds and spirals. In this paper the formation mechanism of folds is examined by a plasma simulation method. It is suggested that folds, as well as curls, can arise from electrostatic shear-induced instabilities. The differences between the two forms are controlled by the presence of ambient ions that must be present to shield the electric field of the precipitating electron charge sheet. It is shown that curls form when the ion sheath thickness is large in comparison with the electron sheet. Folds form when the ion sheath is thin and lags slightly behind the electron guiding centers, setting up an additional electric field that controls the late stages of instability growth.

  12. Quantifying the Role of Different Magnetospheric Plasma Waves in Diffuse Auroral Precipitation

    NASA Astrophysics Data System (ADS)

    Thorne, R. M.; Ni, B.; Li, W.; Zhang, X.; Bortnik, J.

    2015-12-01

    Diffuse auroral pecipitation provides a major source of ionization for the high latitude upper atmosphere, and as such controls the spatial distribution of ionospheric conductivity and its variability during geomagnetic activity. The physical mechanisms responsible for diffuse auroral precipitation have been debated for several decades. But recent detailed modeling of the rates of electron scattering by plasma waves, together with new and improved observations of the wave and particle environment in space, have allowed us to identify the dominant mechanisms responsible for the precipitation of plasma sheet electrons into the atmosphere. At lower invariant latitude (L< 8) a combination of lower and upper band chorus emissions provides the dominant scattering mechanism and can also account for the unique anisotropic pitch angle distribution left in space, which can continue to provide the source for chorus excitation over the dawn side of the magnetosphere. However, at higher L shells the electron anisotropy is insufficient to cause chorus excitation, but the residual loss cone distribution can excite electrostatic cyclotron harmonic (ECH) waves, which are the dominant scattering agent at higher invariant latitude. Both chorus and ECH waves are capable of causing electron scattering at the strong diffusion rate during more intense geomagnetic activity, and this can lead to a significant reduction of plasma sheet electron flux able to reach the dayside, which acconts fore the strong day-night asymmetry of diffuse auroral precipitation.

  13. Cassini Observations During the Saturn Auroral Campaign of Spring 2013 (Invited)

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; Lamy, L.; Gurnett, D. A.; Mitchell, D. G.; Dougherty, M. K.; Bunce, E. J.; Badman, S. V.; Burton, M. E.; Crary, F. J.; Pryor, W. R.; Baines, K. H.; Dyudina, U.; Nichols, J. D.; Stallard, T.; Luhmann, J. G.; Zheng, Y.; Hansen, K. C.

    2013-12-01

    During April and May 2013, a concerted effort to study Saturn's auroras was mounted using multi-wavelength observations from Cassini and a number of Earth-based observations. This paper will focus on the Cassini observations acquired during the campaign with an emphasis on the fields and particle observations and Saturn Kilometric Radiation, in particular. It has been shown that the integrated power of Saturn Kilometric Radiation (SKR) provides a good proxy for auroral activity and there is at least a qualitative correlation between auroral brightness and SKR intensity. While the SKR observations can be complicated by beaming issues, they provide a reasonable, continuous context within which to place other observations. We compare the time history of SKR intensity with models of the solar wind input based on models which propagate 1 AU observations to the distance of Saturn. Further, direction-finding measurements of the SKR reveal the source of the SKR and these can be related to Earth-based and Cassini-based observations of the auroras. In this paper we will use the SKR observations to construct the evolution of auroral activity and place other in situ and remote sensing observations within this context.

  14. Propagation of a westward traveling surge and the development of persistent auroral features

    SciTech Connect

    Craven, J.D.; Frank, L.A. ); Akasofu, S.I. )

    1989-06-01

    Imaging instrumentation on board the spacecraft Dynamics Explorer 1 (DE 1) is used to observe the large-scale motion of a surge over 7,000 km along the auroral oval from near local midnight. Average speed of the surge is 2.2 km/s. Ground-based observations at Fort Yukon, Alaska, show the classical looped, multiple-arc structure of a westward traveling surge as it passes overhead. Within the 6-min temporal resolution provided with DE 1, the surge advances initially at a speed of about 8 km/s followed by a steady decline to about 1 km/s over a period of 17 min. This sequence is then repeated a second time, beginning with a significant intensification of the surge form. This intense surge activity is not accompanied by significant auroral activity near magnetic midnight. Following passage of the surge, persistent and localized bright emission regions remain along the auroral oval for several tens of minutes. Average separation distances are approximately 700 km. If these persistent features identify the sites of individual stepwise advances of the surge, the average time per advance is about 5 min.

  15. Mirror instability and origin of morningside auroral structure

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.; Schulz, M.; Fennell, J. F.; Kishi, A. M.

    1983-01-01

    Auroral optical imagery shows marked differences between auroral features of the evening and morning sectors: the separation between diffuse and discrete auroras in the evening sector is not distinct in the morning sector, which is dominated by auroral patches and multiple banded structures aligned along some direction. Plasma distribution function signatures also show marked differences: downward electron beams and inverted-V signatures prefer the evening sector, while the electron spectra on the morning sector are similar to the diffuse aurora. A theory of morningside auroras consistent with these features was constructed. The theory is based on modulation of the growth rates of electron cyclotron waves by the mirror instability, which is in turn driven by inward-convected ions that have become anisotropic. This modulation produces alternating bands of enhanced and reduced electron precipitation which approximate the observed multiple auroral bands and patches of the morning sector.

  16. Generation of auroral turbulence through the magnetosphere-ionosphere coupling

    NASA Astrophysics Data System (ADS)

    Watanabe, Tomo-Hiko; Kurata, Hiroaki; Maeyama, Shinya

    2016-12-01

    The shear Alfvén waves coupled with the ionospheric density fluctuations in auroral regions of a planetary magnetosphere are modeled by a set of the reduced magnetohydrodynamic and two-fluid equations. When the drift velocity of the magnetized plasma due to the background electric field exceeds a critical value, the magnetosphere-ionosphere (M-I) coupling system is unstable to the feedback instability which leads to formation of auroral arc structures with ionospheric density and current enhancements. As the feedback (primary) instability grows, a secondary mode appears and deforms the auroral structures. A perturbative (quasilinear) analysis clarifies the secondary growth of the Kelvin-Helmholtz type instability driven by the primary instability growth in the feedback M-I coupling. In the nonlinear stage of the feedback instability, furthermore, auroral turbulence is spontaneously generated, where the equipartition of kinetic and magnetic energy is confirmed in the quasi-steady turbulence.

  17. Mirror instability and the origin of morningside auroral structure

    SciTech Connect

    Chiu, Y.T.; Schulz, M.; Fennell, J.F.; Kishi, A.M.

    1983-05-01

    Auroral optical imagery shows marked differences between auroral features of the evening and morning sectors: The separation between diffuse and discrete auroras in the evening sector is not distinct in the morning sector, which is dominated by auroral patches and multiple banded structures aligned along some direction. Plasma distribution function signatures also show marked differences: downward electron beams and inverted-V signatures prefer the evening sector, while the electron spectra on the morning sector are similar to the diffuse aurora. We have constructed a theory of morningside auroras consistent with these features. The theory is based on modulation of the growth rates of electron cyclotron waves by the mirror instability, which is in turn driven by inward-convected ions that have become anisotropic. This modulation produces alternating bands of enhanced and reduced electron precipitation which approximate the observed multiple auroral bands and patches of the morning sector.

  18. Semantic Support Environment for Research Activity

    ERIC Educational Resources Information Center

    Ismail, Maizatul Akmar; Yaacob, Mashkuri; Kareem, Sameem Abdul

    2008-01-01

    Scholarly activities are a collection of academic related activities such as research, teaching and consultation work which result in research outputs such as journals, theses and articles in proceedings. The output will then be disseminated to researchers all over the world by means of the WWW. The four pillars of this scholarship i.e. discovery,…

  19. 38 CFR 1.488 - Research activities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Research activities. 1... PROVISIONS Disclosures Without Patient Consent § 1.488 Research activities. Subject to the provisions of 38 U... disclosed for the purpose of conducting scientific research. (a) Information in individually...

  20. Auroral magnetosphere-ionosphere coupling: A brief topical review

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.; Schulz, M.; Cornwall, J. M.

    1979-01-01

    Auroral arcs result from the acceleration and precipitation of magnetospheric plasma in narrow regions characterized by strong electric fields both perpendicular and parallel to the earth's magnetic field. The various mechanisms that were proposed for the origin of such strong electric fields are often complementary Such mechanisms include: (1) electrostatic double layers; (2) double reverse shock; (3) anomalous resistivity; (4) magnetic mirroring of hot plasma; and (5) mapping of the magnetospheric-convection electric field through an auroral discontinuity.

  1. Networked high-speed auroral observations combined with radar measurements for multi-scale insights

    NASA Astrophysics Data System (ADS)

    Hirsch, M.; Semeter, J. L.

    2015-12-01

    Networks of ground-based instruments to study terrestrial aurora for the purpose of analyzing particle precipitation characteristics driving the aurora have been established. Additional funding is pouring into future ground-based auroral observation networks consisting of combinations of tossable, portable, and fixed installation ground-based legacy equipment. Our approach to this problem using the High Speed Tomography (HiST) system combines tightly-synchronized filtered auroral optical observations capturing temporal features of order 10 ms with supporting measurements from incoherent scatter radar (ISR). ISR provides a broader spatial context up to order 100 km laterally on one minute time scales, while our camera field of view (FOV) is chosen to be order 10 km at auroral altitudes in order to capture 100 m scale lateral auroral features. The dual-scale observations of ISR and HiST fine-scale optical observations may be coupled through a physical model using linear basis functions to estimate important ionospheric quantities such as electron number density in 3-D (time, perpendicular and parallel to the geomagnetic field).Field measurements and analysis using HiST and PFISR are presented from experiments conducted at the Poker Flat Research Range in central Alaska. Other multiscale configuration candidates include supplementing networks of all-sky cameras such as THEMIS with co-locations of HiST-like instruments to fuse wide FOV measurements with the fine-scale HiST precipitation characteristic estimates. Candidate models for this coupling include GLOW and TRANSCAR. Future extensions of this work may include incorporating line of sight total electron count estimates from ground-based networks of GPS receivers in a sensor fusion problem.

  2. First light from a kilometer-baseline Scintillation Auroral GPS Array

    NASA Astrophysics Data System (ADS)

    Datta-Barua, S.; Su, Y.; Deshpande, K.; Miladinovich, D.; Bust, G. S.; Hampton, D.; Crowley, G.

    2015-05-01

    We introduce and analyze the first data from an array of closely spaced Global Positioning System (GPS) scintillation receivers established in the auroral zone in late 2013 to measure spatial and temporal variations in L band signals at 100-1000 m and subsecond scales. The seven receivers of the Scintillation Auroral GPS Array (SAGA) are sited at Poker Flat Research Range, Alaska. The receivers produce 100 s scintillation indices and 100 Hz carrier phase and raw in-phase and quadrature-phase samples. SAGA is the largest existing array with baseline lengths of the ionospheric diffractive Fresnel scale at L band. With an initial array of five receivers, we identify a period of simultaneous amplitude and phase scintillation. We compare SAGA power and phase data with collocated 630.0 nm all-sky images of an auroral arc and incoherent scatter radar electron precipitation measurements, to illustrate how SAGA can be used in multi-instrument observations for subkilometer-scale studies.

  3. First light from a kilometer-baseline Scintillation Auroral GPS Array.

    PubMed

    Datta-Barua, S; Su, Y; Deshpande, K; Miladinovich, D; Bust, G S; Hampton, D; Crowley, G

    2015-05-28

    We introduce and analyze the first data from an array of closely spaced Global Positioning System (GPS) scintillation receivers established in the auroral zone in late 2013 to measure spatial and temporal variations in L band signals at 100-1000 m and subsecond scales. The seven receivers of the Scintillation Auroral GPS Array (SAGA) are sited at Poker Flat Research Range, Alaska. The receivers produce 100 s scintillation indices and 100 Hz carrier phase and raw in-phase and quadrature-phase samples. SAGA is the largest existing array with baseline lengths of the ionospheric diffractive Fresnel scale at L band. With an initial array of five receivers, we identify a period of simultaneous amplitude and phase scintillation. We compare SAGA power and phase data with collocated 630.0 nm all-sky images of an auroral arc and incoherent scatter radar electron precipitation measurements, to illustrate how SAGA can be used in multi-instrument observations for subkilometer-scale studies.

  4. Effect of auroral substorms on the ionospheric range spread-F enhancements at high southern midlatitudes using real time vertical-sounding ionograms

    NASA Astrophysics Data System (ADS)

    Hajkowicz, Lech A.

    2016-03-01

    A comprehensive study has been undertaken on the effect of magnetic substorm onsets (as deduced from the auroral hourly electrojet AE-index) on the occurrence of high midlatitude (or sub-auroral latitude) ionospheric range spread-F (Sr). Unlike the previous reports real-time ionograms were used in this analysis thus eliminating ambiguities stemming from the correlating secondary evidence of spread-F with auroral substorms. The Australian southernmost ionosonde station Hobart (51.6°S geom.) proved to be uniquely suitable for the task as being sufficiently close to the southern auroral zone. Sr was assigned in km to each hourly nighttime ionogram at two sounding frequencies: Sr1 (at 2 MHz) and Sr2 (at 6 MHz) for four months in 2002: January and June (representing southern summer and winter solstices), and March and September (representing autumn and vernal equinoxes). It is evident that the southern winter solstitial period (June) is associated with high endemic midlatitude spread-F activity. All other seasons are closely linked with temporal sequences of enhanced spread-F activity following substorm onsets. For the first time it was possible not only find a simultaneous occurrence pattern of these diverse phenomena but to deduce numerical characteristics of the response of midlatitude ionosphere to the global auroral stimulus. Excellent case events, hitherto unpublished, are shown illustrating the presence of the AE peaks (in nT) being ahead of Sr peaks (in km) by a time shift ∆t (in h). Sr1 magnitude showed a significant correlation with the magnitudes of the preceding AE with a correlation coefficient (r) of 0.51 (probability of the occurrence by chance less than 0.01). Sr2 peaks were more sensitive to auroral disturbances but were not correlated with the AE magnitude variations. The time shift (∆t) was on average 4 h with a standard deviation of 3 h. The general pattern in the occurrence of magnetic substorms and spread-F is very similar. A number of

  5. Custom auroral electrojet indices calculated by using MANGO value-added services

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.; Moore, W. B.; King, T. A.

    2009-12-01

    A set of computational routines called MANGO, Magnetogram Analysis for the Network of Geophysical Observatories, is utilized to calculate customized versions of the auroral electrojet indices, AE, AL, and AU. MANGO is part of an effort to enhance data services available to users of the Heliophysics VxOs, specifically for the Virtual Magnetospheric Observatory (VMO). The MANGO value-added service package is composed of a set of IDL routines that decompose ground magnetic field observations to isolate secular, diurnal, and disturbance variations of magnetic field disturbance, station-by-station. Each MANGO subroutine has been written in modular fashion to allow "plug and play"-style flexibility and each has been designed to account for failure modes and noisy data so that the programs will run to completion producing as much derived data as possible. The capabilities of the MANGO service package will be demonstrated through their application to the study of auroral electrojet current flow during magnetic substorms. Traditionally, the AE indices are calculated by using data from about twelve ground stations located at northern auroral zone latitudes spread longitudinally around the world. Magnetogram data are corrected for secular variation prior to calculating the standard version of the indices but the data are not corrected for diurnal variations. A custom version of the AE indices will be created by using the MANGO routines including a step to subtract diurnal curves from the magnetic field data at each station. The custom AE indices provide more accurate measures of auroral electrojet activity due to isolation of the sunstorm electrojet magnetic field signiture. The improvements in the accuracy of the custom AE indices over the tradition indices are largest during the northern hemisphere summer when the range of diurnal variation reaches its maximum.

  6. Coordinated ground and space measurements of auroral surge over South Pole. Technical report

    SciTech Connect

    Rosenberg, T.J.; Detrick, D.L.; Mizera, P.F.; Gorney, D.J.; Berkey, F.T.

    1988-02-01

    Coincident ground-based and satellite observations are presented of a premidnight auroral surge over Amundsen-Scott South Pole station. The set of near-simultaneous measurements provides an excellent opportunity to gain a more-quantitative understanding of the nature of premidnight substorm activity at high geomagnetic latitudes. The surge produced a rapid onset of cosmic radio noise absorption at the station. On the polar-orbiting DMSP-F6 spacecraft, intense x-ray emissions with E > 2-keV energy were imaged 1 to 2 deg magnetically equatorward of the South Pole approximately 1 min prior to the peak of the absorption event. The precipitating electron spectrum determined from the x-ray measurements could be characterized by an e-folding energy of approx. 11 keV and is found to be adequate to account for the cosmic noise absorption and maximum auroral luminosity recorded at South Pole. Photometer, all-sky camera, riometer, and magnetometer data are used to estimate the velocity of motion and spatial extent of the auroral precipitation and the ionospheric currents associated with the surge.

  7. Coordinated ground and space measurements of an auroral surge over South Pole

    SciTech Connect

    Rosenberg, T.J.; Detrick, D.L.; Mizera, P.F.; Gorney, D.J.; Berkey, F.T.; Eather, R.H.; Lanzerotti, L.J.

    1987-10-01

    Coincident ground-based and satellite observations are presented of a premidnight auroral surge over Amundsen-Scott South Pole station. The set of near-simultaneous measurements provides an excellent opportunity to gain a more quantitative understanding of the nature of premidnight substorm activity at high geomagnetic latitudes. The surge produced a rapid onset of cosmic radio noise absorption at the station. On the polar-orbiting DMSP F6 spacecraft, intense X ray emissions with E>2 keV energy were imaged 1/sup 0/ to 2/sup 0/ magnetically equatorward of South Pole approximately 1 min prior to the peak of the absorption event. The spectrum of precipitating electrons determined from the X ray measurements could be characterized by an e-folding energy of approx.11 keV and is found to be adequate to account for the cosmic noise absorption and maximum auroral luminosity recorded at South Pole. Photometer, all-sky camera, riometer, and magnetometer data are used to estimate the velocity of motion and spatial extent of the auroral precipitation and the ionospheric currents associated with the surge. The electron precipitation region is deduced to have a latitudinal scale size of <100 km and to move poleward with a speed of approx.1--2 km/s coincident with the movement of a westward electrojet.

  8. Study of AKR hollow pattern characteristics at sub-auroral regions

    NASA Astrophysics Data System (ADS)

    Boudjada, Mohammed Y.; Sawas, Sami; Galopeau, Patrick; Berthelier, Jean-Jacques; Schwingenschuh, Konrad

    2014-05-01

    The Earth's auroral kilometric radiation (AKR) is expected to exhibit a hollow pattern similar to that reported for the comparable emissions from Jupiter (e.g. Jovian decametric emissions - DAM). The hollow pattern is a hollow cone beam with apex at the point of AKR emission, axis tangent to the magnetic field direction, and an opening angle of the order of 80°. The properties of the hollow cone can be derived from the so-called dynamic spectrum which displays the radiation versus the observation time and the frequency. We analyze the auroral kilometric radiation recorded by the electric field experiment (ICE) onboard DEMETER micro-satellite. The dynamic spectra lead us to study the occurrence of the AKR recorded in the sub-auroral regions when the micro-satellite was at altitudes of about 700 km. We address in this contribution issues concerning the characteristics (occurrence, latitude and longitude) of the AKR hollow beam and their relations to the seasonal and solar activity variations.

  9. Effects of substorm electrojet on declination along concurrent geomagnetic latitudes in the northern auroral zone

    NASA Astrophysics Data System (ADS)

    Edvardsen, Inge; Johnsen, Magnar G.; Løvhaug, Unni P.

    2016-10-01

    The geomagnetic field often experiences large fluctuations, especially at high latitudes in the auroral zones. We have found, using simulations, that there are significant differences in the substorm signature, in certain coordinate systems, as a function of longitude. This is confirmed by the analysis of real, measured data from comparable locations. Large geomagnetic fluctuations pose challenges for companies involved in resource exploitation since the Earth's magnetic field is used as the reference when navigating drilling equipment. It is widely known that geomagnetic activity increases with increasing latitude and that the largest fluctuations are caused by substorms. In the auroral zones, substorms are common phenomena, occurring almost every night. In principle, the magnitude of geomagnetic disturbances from two identical substorms along concurrent geomagnetic latitudes around the globe, at different local times, will be the same. However, the signature of a substorm will change as a function of geomagnetic longitude due to varying declination, dipole declination, and horizontal magnetic field along constant geomagnetic latitudes. To investigate and quantify this, we applied a simple substorm current wedge model in combination with a dipole representation of the Earth's magnetic field to simulate magnetic substorms of different morphologies and local times. The results of these simulations were compared to statistical data from observatories and are discussed in the context of resource exploitation in the Arctic. We also attempt to determine and quantify areas in the auroral zone where there is a potential for increased space weather challenges compared to other areas.

  10. ;Long-hissler; fine structure within auroral hiss: A review and synthesis

    NASA Astrophysics Data System (ADS)

    Kim, Howard F.; LaBelle, James; Spasojević, Maria

    2017-04-01

    One of the most prominent fine-structures of auroral hiss is the ;long-hissler;, defined here as a dispersed feature embedded within broadband auroral hiss emissions in the frequency range 1-40 kHz and lasting longer than 0.3 s. While theory is limited, there is evidence that hisslers can be used in remote sensing of density characteristics at altitudes of thousands of km. By applying an automatic threshold algorithm to VLF data collected at South Pole 2230-0130 UT daily during June-August 2014, 22 h of auroral hiss are identified on 49 of 93 days analyzed, for an occurrence rate of 9.7% during the applicable MLT interval. From manual inspection of these intervals, 414 groups (trains) of long hisslers are identified on 34 of the 49 days on which hiss occurred. Median lower (upper) frequency bounds of these features are 8 (22) kHz, median frequency-time slope is -10 kHz/s, and median hissler repetition time within a train (hissler period) is 1.2 s. Hissler period and frequency-time slope are inversely related. Data from previous studies are reviewed to provide a comprehensive description of the phenomenon. Contrary to some previous studies, subsequent long hissler features are found to commonly overlap in time, and no evidence is found for an inverse relationship between hissler train duration and geomagnetic activity.

  11. Development of Ground-Based Auroral Photometry Techniques Using In-Situ Electron Precipitation Measurements from the GREECE Mission

    NASA Astrophysics Data System (ADS)

    Grubbs, G. A., II; Samara, M.; Michell, R.; Hampton, D.

    2014-12-01

    The Ground-to-Rocket Electrodynamics-Electrons Correlative Experiment (GREECE) mission successfully launched from Poker Flat, Alaska on 03 March 2014 at 11:09:50 UT and reached an apogee of approximately 335 km during a luminous auroral event. Multiple ground-based electron-multiplying charge-coupled device (EMCCD) imagers were positioned at Venetie, Alaska and aimed along magnetic zenith in order to observe the brightness of different auroral emission lines (427.8, 557.7, and 844.6 nm with a 47 degree field of view) at the magnetic footpoint of the payload, near apogee. Emission line brightness data are presented at the footpoint of the rocket flight and correlated with electron characteristics taken by the Acute Precipitating Electron Spectrometer (APES) on-board instrument. Ratios of different auroral emission lines are also compared to previously published methods and models. This research aims to describe the auroral emissions produced from a known precipitating electron distribution, such that we can more accurately use ground-based imaging and photometry to infer the characteristics of the precipitating electrons. These techniques can then be applied over larger scales and longer times, when only multi-spectral imaging data are available with no corresponding in situ data.

  12. Correlated variations of UV and radio emissions during an outstanding Jovian auroral event

    NASA Technical Reports Server (NTRS)

    Prange, R.; Zarka, P.; Ballester, G. E.; Livengood, T. A.; Denis, L.; Carr, T.; Reyes, F.; Bame, S. J.; Moos, H. W.

    1993-01-01

    a significant disturbance in the solar wind, involving the generation of an interplanetary shock and the presence of a CME have interacted with the Jovian magnetosphere at about the time of the auroral event. Both arguments suggest that we may have observed for the first time a magnetic storm-type interaction in an outer planet magnetosphere, affecting simultaneously several auroral processes. Conversely, the observed relationship between the level of UV auroral activity and the detection of decameter emission (DAM), if it were a typical feature, might argue in favour of a more direct and permanent association between the auroral processes leading to UV and radio aurorae, possibly related to 'discrete-arc'-like activity and electron precipitation.

  13. DEMETER observations of bursty MF emissions and their relation to ground-level auroral MF burst

    NASA Astrophysics Data System (ADS)

    Broughton, M. C.; LaBelle, J.; Parrot, M.

    2014-12-01

    A survey of medium frequency (MF) electric field data from selected orbits of the Detection of Electro-Magnetic Emissions Transmitted from Earthquakes (DEMETER) spacecraft reveals 68 examples of a new type of bursty MF emissions occurring at high latitudes associated with auroral phenomena. These resemble auroral MF burst, a natural radio emission observed at ground level near local substorm onsets. Similar to MF burst, the bursty MF waves observed by DEMETER have broadband, impulsive frequency structure covering 1.5-3.0 MHz, amplitudes of 50-100 μV/m, an overall occurrence rate of ˜0.76% with higher occurrence during active times, and strong correlation with auroral hiss. The magnetic local time distribution of the MF waves observed by DEMETER shows peak occurrence rate near 18 MLT, somewhat earlier than the equivalent peak in the occurrence rate of ground level MF burst, though propagation effects and differences in the latitudes sampled by the two techniques may explain this discrepancy. Analysis of solar wind and SuperMAG data suggests that while the bursty MF waves observed by DEMETER are associated with enhanced auroral activity, their coincidence with substorm onset may not be as exact as that of ground level MF burst. One conjunction occurs in which MF burst is observed at Churchill, Manitoba, within 8 min of MF emissions detected by DEMETER on field lines approximately 1000 km southeast of Churchill. These observations may plausibly be associated with the same auroral event detected by ground level magnetometers at several Canadian observatories. Although it is uncertain, the balance of the evidence suggests that the bursty MF waves observed with DEMETER are the same phenomenon as the ground level MF burst. Hence, theories of MF burst generation in the ionosphere, such as beam-generated Langmuir waves excited over a range of altitudes or strong Langmuir turbulence generating a range of frequencies within a narrow altitude range, need to be revisited to

  14. Spectacular ionospheric flow structures associated with substorm auroral onset

    NASA Astrophysics Data System (ADS)

    Gallardo-Lacourt, B. I.; Nishimura, Y.; Lyons, L. R.; Zou, Y.; Angelopoulos, V.; Donovan, E.; Mende, S. B.; Ruohoniemi, J.; McWilliams, K. A.; Nishitani, N.

    2013-12-01

    Auroral observations have shown that brightening at substorm auroral onset consists of azimuthally propagating beads forming along a pre-existing arc. However, the ionospheric flow structure related to this wavy auroral structure has not been previously identified. We present 2-d line-of-sight flow observations and auroral images from the SuperDARN radars and the THEMIS ground-based all-sky-imager array to investigate the ionospheric flow pattern associated with the onset. We have selected events where SuperDARN was operating in the THEMIS mode, which provides measurements along the northward looking radar beam that have time resolution (6 s) comparable to the high time resolution of the imagers and gives us a unique tool to detect properties of flows associated with the substorm onset instability. We find very fast flows (~1000 m/s) that initiated simultaneously with the onset arc beads propagating across the THEMIS-mode beam meridian. The flows show oscillations at ~9 mHz, which corresponds to the periodicity of the auroral beads propagating across the radar beam. 2-d radar measurements also show a wavy pattern in the azimuthal direction with a wavelength of ~74 km, which is close to the azimuthal separation of individual beads, although this determination is limited by the 2 minute radar scan period. These strong correlations (in time and space) between auroral beading and the fast ionospheric flows suggest that these spectacular flows are an important feature of the substorm onset instability within the inner plasma sheet. Also, a clockwise flow shear was observed in association with individual auroral beads, suggesting that such flow shear is a feature of the unstable substorm onset waves.

  15. 38 CFR 1.488 - Research activities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Research activities. 1... PROVISIONS Disclosures Without Patient Consent § 1.488 Research activities. Subject to the provisions of 38 U... paragraphs, patient medical record information covered by §§ 1.460 through 1.499 of this part may...

  16. 38 CFR 1.488 - Research activities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Research activities. 1... PROVISIONS Disclosures Without Patient Consent § 1.488 Research activities. Subject to the provisions of 38 U... paragraphs, patient medical record information covered by §§ 1.460 through 1.499 of this part may...

  17. 38 CFR 1.488 - Research activities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Research activities. 1... PROVISIONS Disclosures Without Patient Consent § 1.488 Research activities. Subject to the provisions of 38 U... paragraphs, patient medical record information covered by §§ 1.460 through 1.499 of this part may...

  18. 38 CFR 1.488 - Research activities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Research activities. 1... PROVISIONS Disclosures Without Patient Consent § 1.488 Research activities. Subject to the provisions of 38 U... paragraphs, patient medical record information covered by §§ 1.460 through 1.499 of this part may...

  19. Representation of the Auroral and Polar Ionosphere in the International Reference Ionosphere (IRI)

    NASA Technical Reports Server (NTRS)

    Bilitza, Dieter; Reinisch, Bodo

    2013-01-01

    This issue of Advances in Space Research presents a selection of papers that document the progress in developing and improving the International Reference Ionosphere (IRI), a widely used standard for the parameters that describe the Earths ionosphere. The core set of papers was presented during the 2010 General Assembly of the Committee on Space Research in Bremen, Germany in a session that focused on the representation of the auroral and polar ionosphere in the IRI model. In addition, papers were solicited and submitted from the scientific community in a general call for appropriate papers.

  20. 42 CFR 2.52 - Research activities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Research activities. 2.52 Section 2.52 Public... OF ALCOHOL AND DRUG ABUSE PATIENT RECORDS Disclosures Without Patient Consent § 2.52 Research... research if the program director makes a determination that the recipient of the patient...

  1. 42 CFR 2.52 - Research activities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Research activities. 2.52 Section 2.52 Public... OF ALCOHOL AND DRUG ABUSE PATIENT RECORDS Disclosures Without Patient Consent § 2.52 Research... research if the program director makes a determination that the recipient of the patient...

  2. 42 CFR 2.52 - Research activities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Research activities. 2.52 Section 2.52 Public... OF ALCOHOL AND DRUG ABUSE PATIENT RECORDS Disclosures Without Patient Consent § 2.52 Research... research if the program director makes a determination that the recipient of the patient...

  3. 42 CFR 2.52 - Research activities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Research activities. 2.52 Section 2.52 Public... OF ALCOHOL AND DRUG ABUSE PATIENT RECORDS Disclosures Without Patient Consent § 2.52 Research... research if the program director makes a determination that the recipient of the patient...

  4. 42 CFR 2.52 - Research activities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Research activities. 2.52 Section 2.52 Public... OF ALCOHOL AND DRUG ABUSE PATIENT RECORDS Disclosures Without Patient Consent § 2.52 Research... research if the program director makes a determination that the recipient of the patient...

  5. An Integrated Extravehicular Activity Research Plan

    NASA Technical Reports Server (NTRS)

    Abercromby, Andrew F. J.; Ross, Amy J.; Cupples, J. Scott

    2016-01-01

    Multiple organizations within NASA and outside of NASA fund and participate in research related to extravehicular activity (EVA). In October 2015, representatives of the EVA Office, the Crew and Thermal Systems Division (CTSD), and the Human Research Program (HRP) at NASA Johnson Space Center agreed on a formal framework to improve multi-year coordination and collaboration in EVA research. At the core of the framework is an Integrated EVA Research Plan and a process by which it will be annually reviewed and updated. The over-arching objective of the collaborative framework is to conduct multi-disciplinary cost-effective research that will enable humans to perform EVAs safely, effectively, comfortably, and efficiently, as needed to enable and enhance human space exploration missions. Research activities must be defined, prioritized, planned and executed to comprehensively address the right questions, avoid duplication, leverage other complementary activities where possible, and ultimately provide actionable evidence-based results in time to inform subsequent tests, developments and/or research activities. Representation of all appropriate stakeholders in the definition, prioritization, planning and execution of research activities is essential to accomplishing the over-arching objective. A formal review of the Integrated EVA Research Plan will be conducted annually. External peer review of all HRP EVA research activities including compilation and review of published literature in the EVA Evidence Book is already performed annually. Coordination with stakeholders outside of the EVA Office, CTSD, and HRP is already in effect on a study-by-study basis; closer coordination on multi-year planning with other EVA stakeholders including academia is being actively pursued. Details of the current Integrated EVA Research Plan are presented including description of ongoing and planned research activities in the areas of: Benchmarking; Anthropometry and Suit Fit; Sensors; Human

  6. Dynamics of a discrete auroral arc

    NASA Technical Reports Server (NTRS)

    Bruening, K.; Goertz, C. K.

    1986-01-01

    Porcupine Flight 4 data were used to determine the field-aligned currents associated with a southward moving discrete auroral arc in the postmidnight sector. Three different methods were used for determining the field-aligned current which should give identical results if the arcs are quasi-stationary and no parallel electric field exists between the payload and the dynamo region of the ionosphere. As long as the rocket is above the arc, the three methods agree. The integral of precipitating electron flux, the local magnetic field perturbations, and the divergence of the horizontal Pedersen current all indicate an upward current of 5 + or - 3 microamperes/sq m. Immediately north of the arc a strong downward current of about 10-20 microamperes/sq m is detected. The magnitude, however, is not well known because the rocket's velocity relative to the arc cannot be clearly established. Further north of the southward moving arc, the two methods that can be applied (magnetic field perturbations and divergence of the horizontal Pedersen current) yield contradictory results not only about the magnitude of the current but also about the direction of the current. It is suggested that this discrepancy is due to time-dependent electric field.

  7. Dynamics of a discrete auroral arc

    NASA Astrophysics Data System (ADS)

    Bruening, K.; Goertz, C. K.

    1986-06-01

    Porcupine Flight 4 data were used to determine the field-aligned currents associated with a southward moving discrete auroral arc in the postmidnight sector. Three different methods were used for determining the field-aligned current which should give identical results if the arcs are quasi-stationary and no parallel electric field exists between the payload and the dynamo region of the ionosphere. As long as the rocket is above the arc, the three methods agree. The integral of precipitating electron flux, the local magnetic field perturbations, and the divergence of the horizontal Pedersen current all indicate an upward current of 5 + or - 3 microamperes/sq m. Immediately north of the arc a strong downward current of about 10-20 microamperes/sq m is detected. The magnitude, however, is not well known because the rocket's velocity relative to the arc cannot be clearly established. Further north of the southward moving arc, the two methods that can be applied (magnetic field perturbations and divergence of the horizontal Pedersen current) yield contradictory results not only about the magnitude of the current but also about the direction of the current. It is suggested that this discrepancy is due to time-dependent electric field.

  8. [Climate chance and research activity].

    PubMed

    Manuel, Celie

    2009-10-26

    There are three main focus areas relevant to health in research related to climate change: 1) disentangling of the complex associations between climate-sensitive risk factors and health 2) guidance as to where, when and how effective health adaptation strategies may be implemented for maximum effect, and 3) health impact assessment (with a focus on health co-benefits) of climate-related policies in other sectors. Further development in each of these areas will provide important opportunities for strengthening health promotion and protection.

  9. Birth and Life of Auroral Arcs Embedded in the Evening Auroral Oval

    NASA Astrophysics Data System (ADS)

    Haerendel, G.; Chaston, C. C.; Frey, H. U.; Amm, O.; Juusola, L.; Nakamura, R.; Seran, E.; Weygand, J. M.

    2011-12-01

    We report on all-sky camera observations at Ft. Simpson during the crossing of the FAST spacecraft on 09 March 2008 at about 19:00 MLT. FAST registered eight auroral arcs with the associated upward currents and two periods of downward currents during the crossing time of five minutes. All arcs were moving equatorward with speeds near 300 m/s. Some of them exhibited local broadening and subsequent unfolding. Most remarkable was the appearance of new arcs at the poleward border of the auroral oval, clearly marked by an Alfvénic arc. The FAST data on energy and energy flux of the precipitating electrons and the jumps of the transverse magnetic perturbation field through the arcs were evaluated for five of the arcs following the formalism of Haerendel [2007]. This led to very consistent values for the integral wave impedance, field-parallel conductance, Alfvénic transit time, arc width, proper motion, and total energy release including the ionospheric dissipation. The most significant result is that all equatorward motions of the arcs were consistent with being proper motions in the rest frame of the ambient plasma. This is observational evidence for the arcs feeding on the magnetic energy liberated by the release of shear stresses in a region of dominantly upward field-aligned currents.

  10. Properties of the Auroral Zone Ionosphere Inferred Using Plasma Contactor Data From the International Space Station

    NASA Astrophysics Data System (ADS)

    Koontz, S. L.; Bering, E. A.; Evans, D. S.; Katz, I.; Gardner, B. M.; Suggs, R. M.; Minow, J. I.; Dalton, P. J.; Ferguson, D. C.; Hillard, G. B.; Counts, J. L.; Barsamian, H.; Kern, J.; Mikatarian, R.

    2001-12-01

    observations order themselves with geomagnetic activity. We will compare the peak densities with auroral energy inputs inferred from electron precipitation monitors on the NOAA-15 and NOAA-16 spacecraft.

  11. Correlated observations of the equatorward diffuse auroral boundary

    SciTech Connect

    Slater, D.W.; Smith, L.L.; Kleckner, E.W.

    1980-02-01

    The equatorward boundary of the diffuse auroral zone, as viewed via the 6300-A (O(/sup 1/D)) emission line, has been examined by using ground-based photometer data. These observations are supplemented with in situ measurements of ionospheric parameters by satellite-borne instrumentation within the photometer field of view. We find high spatial correlation among 6300-A emission, low-energy (E<1 keV) electron precipitation, and the high-latitude recovery of ambient electron density which constitutes the poleward cliff of the main ionospheric trough. Time resolution afforded by this ground-based potical method is especially suited for monitoring the ionospheric signature of this low-energy particle precipitation over broad longitudes. A model is developed of the statistical equatorward boundary of the diffuse aurora as a function of magnetic local time and magnetic activity (as monotored by Kp index). The local time dependence of this boundary exhibits a latitudinal morphology similar to that of the earthward equatorial plasma sheet: that is, asymmetric about local midnight and skewed toward lesser invariant latitude values within the morning sector.

  12. Juno's Earth flyby: the Jovian infrared Auroral Mapper preliminary results

    NASA Astrophysics Data System (ADS)

    Adriani, A.; Moriconi, M. L.; Mura, A.; Tosi, F.; Sindoni, G.; Noschese, R.; Cicchetti, A.; Filacchione, G.

    2016-08-01

    The Jovian InfraRed Auroral Mapper, JIRAM, is an image-spectrometer onboard the NASA Juno spacecraft flying to Jupiter. The instrument has been designed to study the aurora and the atmosphere of the planet in the spectral range 2-5 μm. The very first scientific observation taken with the instrument was at the Moon just before Juno's Earth fly-by occurred on October 9, 2013. The purpose was to check the instrument regular operation modes and to optimize the instrumental performances. The testing activity will be completed with pointing and a radiometric/spectral calibrations shortly after Jupiter Orbit Insertion. Then the reconstruction of some Moon infrared images, together with co-located spectra used to retrieve the lunar surface temperature, is a fundamental step in the instrument operation tuning. The main scope of this article is to serve as a reference to future users of the JIRAM datasets after public release with the NASA Planetary Data System.

  13. Analytic model of aurorally coupled magnetospheric and ionospheric electrostatic potentials

    NASA Technical Reports Server (NTRS)

    Cornwall, J. M.

    1994-01-01

    This paper describes modest but significant improvements on earlier studies of electrostatic potential structure in the auroral region using the adiabatic auroral arc model. This model has crucial nonlinearities (connected, for example. with aurorally produced ionization) which have hampered analysis; earlier work has either been linear, which I will show is a poor approximation or, if nonlinear, either numerical or too specialized to study parametric dependencies. With certain simplifying assumptions I find new analytic nonlinear solutions fully exhibiting the parametric dependence of potentials on magnetospheric (e.g.. cross-tail potential) and ionospheric (e.g., recombination rate) parameters. No purely phenomenological parameters are introduced. The results are in reasonable agreement with observed average auroral potential drops, inverted-V scale sizes, and dissipation rates. The dissipation rate is quite comparable to tail energization and transport rates and should have a major effect on tail and magnetospheric dynamics. This paper gives various relations between the cross-tail potential and auroral parameters (e.g., total parallel currents and potential drops) which can be studied with existing data sets.

  14. Solar Wind Control of the Magnetospheric and Auroral Dynamics

    NASA Astrophysics Data System (ADS)

    Alexeev, I. I.

    2006-02-01

    A dependence of the polar cap magnetic flux on the interplanetary magnetic field and on the solar wind dynamic pressure is studied. The model calculations of the polar cap and auroral oval magnetic fluxes at the ionospheric level are presented. The obtained functions are based on the paraboloid magnetospheric model calculations. The scaling law for the polar cap diameter changing for different subsolar distances is demonstrated. Quiet conditions are used to compare theoretical results with the UV images of the Earth’s polar region obtained onboard the Polar and IMAGE spacecrafts. The model calculations enable finding not only the average polar cap magnetic flux but also the extreme values of the polar cap and auroral oval magnetic fluxes. These values can be attained in the course of the severe magnetic storm. Spectacular aurora often can be seen at midlatitude during severe magnetic storm. In particularly, the Bastille Day storm of July 15 16, 2000, was a severe magnetic storm when auroral displays were reported at midlatitudes. Enhancement of global magnetospheric current systems (ring current and tail current) and corresponding reconstruction of the magnetospheric structure is a reason for the equatorward displacement of the auroral zone. But at the start of the studied event the contracted polar cap and auroral oval were observed. In this case, the sudden solar wind pressure pulse was associated with a simultaneous northward IMF turning. Such IMF and solar wind pressure behavior is a cause of the observed aurora dynamics.

  15. Space Weather Monitoring for ISS Space Environments Engineering and Crew Auroral Observations

    NASA Technical Reports Server (NTRS)

    Minow, Joseph; Pettit, Donald R.; Hartman, William A.

    2012-01-01

    Today s presentation describes how real time space weather data is used by the International Space Station (ISS) space environments team to obtain data on auroral charging of the ISS vehicle and support ISS crew efforts to obtain auroral images from orbit. Topics covered include: Floating Potential Measurement Unit (FPMU), . Auroral charging of ISS, . Real ]time space weather monitoring resources, . Examples of ISS auroral charging captured from space weather events, . ISS crew observations of aurora.

  16. Auroral boundary movement rates during substorm onsets and their correspondence to solar wind and the AL index

    NASA Astrophysics Data System (ADS)

    Andriyas, Tushar

    2016-08-01

    A statistical analysis of the equatorward and poleward auroral boundary movement during substorm onsets, the related solar wind activity, GOES 8 and 10 magnetic field, and the westward auroral electrojet (AL) index is undertaken, during the years 2000-2002. Auroral boundary data were obtained from the British Antarctic Survey (BAS). These boundaries were derived using auroral images from the IMAGE satellite. The timing of the onsets was derived from the Frey et al. (2004) database. Data were also classified based on the peak AL around the onset and the onset latitude, in order to analyze the differences, if any, in the rates of movement. It was found that the absolute ratio of the rate of movement of the mean poleward and equatorward boundaries was slower than the rate of mean movement around the midnight sector. The stronger the onset (in terms of the peak AL around the onset) was, the faster the rate of movement for both the boundaries. This implies that the stronger the AL signature around the onset, the weaker the magnetic field was prior to the onset and the faster it increased after the onset at GOES 8 and 10 locations. The stronger the AL signature, the thicker the latitudinal width of the aurora was, prior to the onset and higher was the increase in the width after the onset, due to large poleward and average equatorward expansion. Magnetotail field line stretching and relaxation rates as measured by GOES were also found to lie in the same order of magnitude. It is therefore concluded that the rates of latitudinal descent prior to a substorm onset and ascent after the onset, of the mean auroral boundaries, corresponds to the rate at which the tail field lines stretch and relax before and after the onset, respectively.

  17. Transmission research activities at NASA Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Lewicki, D. G.

    1990-01-01

    A joint research program, to advance the technology of rotorcraft transmissions, consists of analytical and experimental efforts to achieve the overall goals of reducing transmission weight and noise, while increasing life and reliability. Recent activities in the areas of transmission and related component research are highlighted. Current areas include specific technologies in support of military rotary wing aviation, gearing technology, transmission noise reduction studies, a recent interest in gearbox diagnostics, and advanced transmission system studies. Results of recent activities are presented along with near term research plans.

  18. Cluster Multipoint Observations of the Spatial Structure and Time Development of Auroral Acceleration Region Field-aligned Current Systems, Potentials, and Plasma

    NASA Astrophysics Data System (ADS)

    Hull, A. J.; Chaston, C. C.; Fillingim, M. O.; Frey, H. U.; Bonnell, J. W.; Mozer, F.; Goldstein, M. L.

    2014-12-01

    The auroral acceleration region is an integral part of the magnetosphere-ionosphere electrodynamic system, and plays a key role in the transport of plasma and energy between Earth and space. This region is embedded with field-aligned currents that couple the magnetosphere to the ionosphere and is where parallel electric fields form that accelerate plasma to and from these regions. Though considerable progress has been made, the complex interplay between field-aligned current system formation, the development of parallel electric fields, changes in the plasma constituents, and auroral emissions consequences are not fully understood. The Cluster mission is well suited for studying the structure and dynamics of the auroral acceleration region. Over its lifetime, Cluster has sampled much of this region with closely spaced probes enabling the distinction between temporal effects from spatial variations. Moreover, this data when combined with auroral images from IMAGE or THEMIS GBO-ASI enable an assessment of the auroral emission response to spatial morphology and temporal development of structures seeded in the auroral acceleration region. In this study we present a survey of Cluster multi-point traversals within and just above the auroral acceleration region (≤ 3 Re altitude). In particular we highlight the spatial morphology and developmental sequence of auroral acceleration current systems, potentials and plasma constituents, with the aim of identifying controlling factors, and assessing ionospheric consequences under different conditions. Our results suggest that the "Alfvénic" activity may be an important precursor and perhaps may be playing an essential role in the development of "quasi-static" current systems during quiet and substorm active times. Such events are generally the result of an injection mediated process at or near the plasma sheet boundary layer, resulting in the local expansion of the plasma sheet. Key features of the conversion from Alfv

  19. observation of auroral emissions induced by artificial plasma jets

    NASA Astrophysics Data System (ADS)

    Erlandson, R. E.; Swaminathan, P. K.; Meng, C.-I.; Stoyanov, B. J.; Zetzer, J. I.; Gavrilov, B. G.; Kiselev, Yu. N.; Romanovsky, Yu. A.

    In this paper we present ultraviolet to near infrared spectrographic observations of high-speed artificial plasma jet interactions with the ionosphere. The plasma jets were injected quasi-parallel to the magnetic field at an altitude of 140 km during the Fluxus-1 and -2 experiments. The jets contained aluminum ions and were generated using a shaped-charge device known as an Explosive Type Generator (ETG). Satellite-based spectrographic observations of the plasma jet show typical auroral emission features associated with electron impact excitation. The auroral features include emission at 135.6 nm (OI) and 557.7 nm (OI). The 135.6 nm emission was prompt while the 557.7 nm was observed for 5 seconds. The most likely source of these auroral emissions are ionospheric and magnetospheric electrons that neutralize the plasma jet.

  20. The spatial-temporal ambiguity in auroral modeling

    NASA Technical Reports Server (NTRS)

    Rees, M. H.; Roble, R. G.; Kopp, J.; Abreu, V. J.; Rusch, D. W.; Brace, L. H.; Brinton, H. C.; Hoffman, R. A.; Heelis, R. A.; Kayser, D. C.

    1980-01-01

    The paper examines the time-dependent models of the aurora which show that various ionospheric parameters respond to the onset of auroral ionization with different time histories. A pass of the Atmosphere Explorer C satellite over Poker Flat, Alaska, and ground based photometric and photographic observations have been used to resolve the time-space ambiguity of a specific auroral event. The density of the O(+), NO(+), O2(+), and N2(+) ions, the electron density, and the electron temperature observed at 280 km altitude in a 50 km wide segment of an auroral arc are predicted by the model if particle precipitation into the region commenced about 11 min prior to the overpass.

  1. Polar cap auroral electron fluxes observed with Isis 1

    NASA Technical Reports Server (NTRS)

    Winningham, J. D.; Heikkila, W. J.

    1974-01-01

    Three types of auroral particle precipitation have been observed over the polar caps, well inside the auroral oval, by means of the soft particle spectrometer on the Isis 1 satellite. The first type is a uniform, very soft (about 100 eV) electron 'polar rain' over the entire polar cap; this may well be present with very weak intensity at all times, but it is markedly enhanced during worldwide geomagnetic storms. A second type of precipitation is a structured flux of electrons with energies near 1 keV, suggestive of localized 'polar showers'; it seems likely that these are the cause of the sun-aligned auroral arcs that have been observed during moderately quiet conditions. During periods of intense magnetic disturbance this precipitation can become very intense and exhibit a characteristic pattern that we have come to call a 'polar squall'.

  2. Effects of turbulence on a kinetic auroral arc model

    NASA Technical Reports Server (NTRS)

    Cornwall, J. M.; Chiu, Y. T.

    1981-01-01

    A plasma kinetic model of an inverted-V auroral arc structure which includes the effects of electrostatic turbulence is proposed. In the absence of turbulence, a parallel potential drop is supported by magnetic mirror forces and charge quasi neutrality, with energetic auroral ions penetrating to low altitudes; relative to the electrons, the ions' pitch angle distribution is skewed toward smaller pitch angles. The electrons energized by the potential drop form a current which excites electrostatic turbulence. In equilibrium the plasma is marginally stable. The conventional anomalous resistivity contribution to the potential drop is very small. Anomalous resistivity processes are far too dissipative to be powered by auroral particles. It is concluded that under certain circumstances equilibrium may be impossible and relaxation oscillations set in.

  3. Auroral Kilometric Radiation and Type III Solar Radio Bursts

    NASA Astrophysics Data System (ADS)

    Romantsova, T. V.; Mogilevsky, M. M.; Skalsky, A. A.; Hanasz, J.

    2009-04-01

    Simultaneous wave observations onboard the ISEE-1 and ISEE-3 spacecraft show that onsets of the Auroral Kilometric Radiation frequently coincide with an arrival of type III solar burst (Calvert, 1981). It was supposed that solar burst stimulates maser instability in auroral region and AKR consequently . We present statistical and case studies of events when both type III solar radio bursts and Auroral Kilometric Radiation are recorded simultaneously. AKR was observed onboard the INTERBALL-2 spacecraft orbiting around the Earth by the POLRAD experiment. Wave measurements carried out onboard the Wind, INTEBALL-TAIL and Geotail spacecraft are used to identify unambiguously the type III solar radio bursts. The origin of close relation between onsets of both solar radiation and AKR is discussed and interpreted. Acknowledgements. This work is supported by grant RFBR 06-02-72560.

  4. Accelerated Auroral Zone Ions: Results from the VISIONS Mission

    NASA Astrophysics Data System (ADS)

    Clemmons, J. H.; Lemon, C. L.; Hecht, J. H.; Rowland, D. E.; Pfaff, R. F.; Klenzing, J.

    2013-12-01

    Presented are results from the VISIONS auroral sounding rocket mission. The presentation focuses on the measured fluxes of locally-accelerated ions and the accompanying measurements of electron fluxes, electric and magnetic DC and wave fields, and auroral emissions. The accelerated ions are shown to have their highest energies and most intense fluxes near the poleward auroral boundary, and are present at all down-going pitch angles. They are also proximate to intense fluxes of field-aligned electrons and strong waves, and appear in conjunction with the intensification of an isotropic population of much more energetic ion precipitation. The measurements are interpreted in the context of the 'pressure cooker' mechanism used to explain similar observations, and the implications of this interpretation for the ion outflow process in this event are discussed.

  5. The current-voltage relationship in auroral current sheets

    NASA Technical Reports Server (NTRS)

    Weimer, D. R.; Gurnett, D. A.; Goertz, C. K.; Menietti, J. D.; Burch, J. L.

    1987-01-01

    The current-voltage relation within narrow auroral current sheets is examined through the use of high-resolution data from the high altitude Dynamics Explorer 1 satellite. The north-south perpendicular electric field and the east-west magnetic field are shown for three cases in which there are large amplitude, oppositely directed paired electric fields and narrow current sheets. These data are shown to indicate that there is a linear Ohm's law relationship between the current density and the parallel potential drop within the narrow current sheets. This linear relationship had previously been verified for large-scale auroral formations greater than 20 km wide at the ionosphere. The evidence shown here extends our knowledge down to the scale size of discrete auroral arcs.

  6. Chatanika radar measurements of the electrical properties of auroral arcs

    NASA Astrophysics Data System (ADS)

    Vondrak, R. R.

    Ionospheric parameters measured in the presence of auroral arcs by the incoherent scatter Chatanika radar are used to define properties of the arcs. The radar broadcasts at 3-5 MW with a range resolution of 4.5 km along the radar line-of-sight, and has yielded auroral measurements on the variation of electron density, Hall and Pederson conductivity, horizontal electric fields, electrojet currents, precipitating electron energy flux, and the Joule heating rate. Elevation-scan techniques have been utilized to study the latitude and altitude variation of the ionospheric plasma parameters, and fixed-position scans allow determination of ionization conditions, including the electric fields and the acceleration of precipitating auroral electrons. Arcs in the diffuse aurora have been found to be local conductivity enhancements, while discrete arcs correspond to the boundary plasma sheet and have an asymmetric electric field pattern reduced on the northward side.

  7. Association of plasma sheet variations with auroral changes during substorms

    SciTech Connect

    Hones, E.W. Jr.; Craven, J.D.; Frank, L.A.; Parks, G.K.

    1988-01-01

    Images of the southern auroral oval taken by the University of Iowa auroral imaging instrumentation on the Dynamics Explorer 1 satellite during an isolated substorm are correlated with plasma measurements made concurrently by the ISEE 1 satellite in the magnetotail. Qualitative magnetic field configuration changes necessary to relate the plasma sheet boundary location to the latitude of the auroras are discussed. Evidence is presented that the longitudinal advances of the auroras after expansive phase onset are mappings of a neutral line lengthening across the near-tail. We observe a rapid poleward auroral surge, occurring about 1 hour after expansive phase onset, to coincide with the peak of the AL index and argue that the total set of observations at that time is consistent with the picture of a /open quotes/poleward leap/close quotes/ of the electrojet marking the beginning of the substorm's recovery. 9 refs. 3 figs.

  8. First Observations of 5fce Auroral Roar Emissions

    NASA Astrophysics Data System (ADS)

    Labelle, J. W.

    2012-12-01

    Auroral radio emissions reveal physics of beam-plasma interactions and provide possibilities to remotely sense ionospheric plasma processes. Sato et al. [2012] recently discovered that auroral roar emissions, long known to occur at two and three times the electron gyrofrequency (fce), also occur at 4fce. Using data from wave receivers in the British Antarctic Survey Automatic Geophysical Observatories (BAS AGOs), we confirm the existence of 4fce-roars and observe for the first time 5fce-roars. A search at higher frequencies did not find higher harmonics, however. Both 4fce- and 5fce-roars only occur in sunlit conditions near the summer soltices. The harmonic emissions scale as expected with the strength of the geomagnetic field, and combining data from four stations with a wide range of magnetic field strengths suggests that the source height of the 4fce may lie around 245 km, significantly lower than the ˜ 275 km estimated for 2fce-roars. These observations show that the auroral roar generation mechanism acts under a broader set of plasma densities than previously considered, highlight how ubiquitous and robust the mechanism must be in different plasma environments, and suggest a broader application for remote sensing methods exploiting auroral roar, such as those described by Weatherwax et al. [2002]. References: Sato, Y., T. Ono, N. Sato, and Y. Ogawa, First observations of 4fce auroral roar emissions, Geophys. Res. Lett., 39, L07101, doi:10.1029/2012GL051205, 2012. Weatherwax, A.T., P.H. Yoon, and J. LaBelle, Model results and interpretation related to topside observations of auroral roar, J. Geophys. Res., 107, 10.1029/2001JA000315, 2002.

  9. Overview of Langley activities in active controls research

    NASA Technical Reports Server (NTRS)

    Abel, I.; Newsom, J. R.

    1981-01-01

    The application of active controls technology to reduce aeroelastic response of aircraft structures offers a potential for significant payoffs in terms of aerodynamic efficiency and weight savings. The activities of the Langley Research Center (laRC) in advancing active controls technology. Activities are categorized into the development of appropriate analysis tools, control law synthesis methodology, and experimental investigations aimed at verifying both analysis and synthesis methodology.

  10. Feedback between neutral winds and auroral arc electrodynamics

    NASA Technical Reports Server (NTRS)

    Lyons, L. R.; Walterscheid, R. L.

    1986-01-01

    The feedback between neutral atmospheric winds and the electrodynamics of a stable, discrete auroral arc is analyzed. The ionospheric current continuity equation and the equation for neutral gas acceleration by ion drag are solved simultaneously, as a function of time. The results show that, in general, the electric field in the ionosphere adjusts to neutral wind acceleration so as to keep auroral field-aligned currents and electron acceleration approximately independent of time. It is thus concluded that the neutral winds that develop as a result of the electrodynamical forcing associated with an arc do not significantly affect the intensity of the arc.

  11. Backward wave cyclotron-maser emission in the auroral magnetosphere.

    PubMed

    Speirs, D C; Bingham, R; Cairns, R A; Vorgul, I; Kellett, B J; Phelps, A D R; Ronald, K

    2014-10-10

    In this Letter, we present theory and particle-in-cell simulations describing cyclotron radio emission from Earth's auroral region and similar phenomena in other astrophysical environments. In particular, we find that the radiation, generated by a down-going electron horseshoe distribution is due to a backward-wave cyclotron-maser emission process. The backward wave nature of the radiation contributes to upward refraction of the radiation that is also enhanced by a density inhomogeneity. We also show that the radiation is preferentially amplified along the auroral oval rather than transversely. The results are in agreement with recent Cluster observations.

  12. Accession Medical Standards Analysis and Research Activity

    DTIC Science & Technology

    2010-01-01

    Chief, Accession Medical Standards Analysis & Research Activity Li Yuanzhang, PhD Senior Statistician Department of Epidemiology David N...ORGANIZATION NAME(S) AND ADDRESS(ES) AMSARA, Department of Epidemiology , Division of Preventive Medicine Walter Reed Army Institute of Research 503... Epidemiology of Injury form the Assessment of Recruit Strength and Motivation study ARMS) and Program

  13. Fine Scale Structure observed in the Total Electron Content above the Sub-Auroral, Auroral, and Polar Ionosphere

    NASA Astrophysics Data System (ADS)

    Coster, A. J.; Thomas, E. G.; Vierinen, J.; Rideout, W. E.

    2015-12-01

    This paper details recent improvements in TEC observations made in the sub-auroral, auroral, and polar regions. The goal is high-resolution measurements of both medium and fine-scale TEC-gradients. To achieve this, the number of GNSS receivers processed was more than doubled, due to agreements made with multiple government and commercial agencies, such as those involved with highway transportation and precision farming. Following the increase in GNSS observations, additional improvements were made in the MIT Haystack GNSS data processing algorithms, allowing for finer grid spacing of the output TEC data. Merging data sets also increased sensitivity. Scintillation data from several GNSS receivers have been overlaid on top of all-sky camera images showing evidence of aurora. These data sets have been merged with the measured background TEC to monitor the development both medium and fine-scale TEC gradients. Data from multiple geomagnetic storms and auroral events in this solar cycle will be presented.

  14. [Research activities in Kobe-Indonesia Collaborative Research Centers].

    PubMed

    Utsumi, Takako; Hayashi, Yoshitake; Hotta, Hak

    2013-01-01

    Kobe-Indonesia Collaborative Research Center was established in Institute of Tropical Disease (ITD), Airlangga University, Surabaya, Indonesia in 2007 under the program of ''Founding Research Centers for Emerging and Reemerging Infectious Diseases'' supported by the Ministry of Education, Culture, Sports, Science and Technology, Japan, and then it has been under the Japan Initiative for Global Research Network on Infectious Diseases (J-GRID) since 2010. Japanese researchers have been stationed at ITD, conducting joint researches on influenza, viral hepatitis, dengue and infectious diarrhea. Also, another Japanese researcher has been stationed at Faculty of Medicine, University of Indonesia, Jakarta, carrying out joint researches on'' Identification of anti-hepatitis C virus (HCV) substances and development of HCV and dengue vaccines'' in collaboration with University of Indonesia and Airlangga University through the Science and Technology Research Partnership for Sustainable Development (SATREPS) supported by the Japan Science and Technology Agency (JST) and Japan International Cooperation Agency (JICA) since 2009. In this article, we briefly introduce the background history of Kobe University Research Center in Indonesia, and discuss the research themes and outcomes of J-GRID and SATREPS activities.

  15. Research on Mobile Learning Activities Applying Tablets

    ERIC Educational Resources Information Center

    Kurilovas, Eugenijus; Juskeviciene, Anita; Bireniene, Virginija

    2015-01-01

    The paper aims to present current research on mobile learning activities in Lithuania while implementing flagship EU-funded CCL project on application of tablet computers in education. In the paper, the quality of modern mobile learning activities based on learning personalisation, problem solving, collaboration, and flipped class methods is…

  16. Search for auroral belt E-parallel fields with high-velocity barium ion injections

    NASA Technical Reports Server (NTRS)

    Heppner, J. P.; Ledley, B. G.; Miller, M. L.; Marionni, P. A.; Pongratz, M. B.

    1989-01-01

    In April 1984, four high-velocity shaped-charge Ba(+) injections were conducted from two sounding rockets at 770-975 km over northern Alaska under conditions of active auroral and magnetic disturbance. Spatial ionization (brightness) profiles of high-velocity Ba(+) clouds from photometric scans following each release were found to be consistent with the 28-sec theoretical time constant for Ba photoionization determined by Carlsten (1975). These observations therefore revealed no evidence of anomalous fast ionization predicted by the Alfven critical velocity hypothesis.

  17. Spatial Relationships of Auroral Particle Acceleration Relative to High Latitude Plasma Boundaries

    NASA Technical Reports Server (NTRS)

    Ghielmetti, Arthur G.

    1997-01-01

    This final report describes the activities under NASA contract to Lockheed Missiles and Space Company. It covers the period from 10-1-94 to 12-31-97. The objective of this investigation is to identify and characterize the spatial relationships of auroral particle acceleration features relative to the characteristic transition features in the surrounding polar ionospheric plasmas. Due to the reduced funding level approved for this contract, the original scope of the proposed work was readjusted with the focus placed on examining spatial relationships with respect to particle structures.

  18. Auroral evidence of radial transport at Jupiter during January 2014

    NASA Astrophysics Data System (ADS)

    Gray, R. L.; Badman, S. V.; Bonfond, B.; Kimura, T.; Misawa, H.; Nichols, J. D.; Vogt, M. F.; Ray, L. C.

    2016-10-01

    We present Jovian auroral observations from the 2014 January Hubble Space Telescope (HST) campaign and investigate the auroral signatures of radial transport in the magnetosphere alongside contemporaneous radio and Hisaki EUV data. HST FUV auroral observations on day 11 show, for the first time, a significantly superrotating polar spot poleward of the main emission on the dawnside. The spot transitions from the polar to main emission region in the presence of a locally broad, bright dawnside main emission feature and two large equatorward emission features. Such a configuration of the main emission region is also unreported to date. We interpret the signatures as part of a sequence of inward radial transport processes. Hot plasma inflows from tail reconnection are thought to flow planetward and could generate the superrotating spot. The main emission feature could be the result of flow shears from prior hot inflows. Equatorward emissions are observed. These are evidence of hot plasma injections in the inner magnetosphere. The images are thought to be part of a prolonged period of reconnection. Radio emissions measured by Wind suggest that hectometric (HOM) and non-Io decametric (DAM) signatures are associated with the sequence of auroral signatures, which implies a global magnetospheric disturbance. The reconnection and injection interval can continue for several hours.

  19. Eyewitness Reports of the Great Auroral Storm of 1859

    NASA Technical Reports Server (NTRS)

    Green, James L.; Boardsen, Scott; Odenwald, Sten; Humble, John; Pazamickas, Katherine A.

    2005-01-01

    The great geomagnetic storm of 1859 is really composed of two closely spaced massive worldwide auroral events. The first event began on August 28th and the second began on September 2nd. It is the storm on September 2nd that results from the Carrington-Hodgson white light flare that occurred on the sun September l&. In addition to published scientific measurements; newspapers, ship logs and other records of that era provide an untapped wealth of first hand observations giving time and location along with reports of the auroral forms and colors. At its height, the aurora was described as a blood or deep crimson red that was so bright that one "could read a newspaper by." Several important aspects of this great geomagnetic storm are simply phenomenal. Auroral forms of all types and colors were observed to latitudes of 25deg and lower. A significant portion of the world's 125,000 miles of telegraph lines were also adversely affected. Many of - which were unusable for 8 hours or more and had a small but notable economic impact. T h s paper presents only a select few available first hand accounts of the Great Auroral Event of 1859 in an attempt to give the modern reader a sense of how this spectacular display was received by the public from many places around the globe and present some other important historical aspects of the storm.

  20. Equatorward evolution of auroras from the poleward auroral boundary

    NASA Astrophysics Data System (ADS)

    Saka, O.; Hayashi, K.; Thomsen, M. F.

    2016-07-01

    An all-sky imager installed at the midnight sector in Dawson City (66.0° in geomagnetic latitude) recorded the equatorward evolution of auroras from the auroral poleward boundary. The auroras evolved as shear layers expanding southeastward with velocities of 1-4 km/s, referred to as N-S auroras, and occurred during the transient intensification of the convection electric fields in the nighttime magnetosphere, as inferred from an electron spectrogram at geosynchronous altitudes. A continuous increase in the inclination angle of the field lines and magnetic field perturbations associated with propagating ionospheric loop currents were observed in the auroral zone during the N-S auroras. Simultaneously, Pc4 pulsations were observed at low latitudes from night to day sectors. We conclude the following: (1) the N-S auroras are an auroral manifestation of the earthward drift of plasma sheet electrons in the equatorial plane associated with transient and localized convection electric fields; (2) the Pc4 pulsations are produced in the magnetosphere by plasma sheet ions in the plasmasphere. The localized convection fields produce a vortical motion of plasmas in the equatorial plane, which may initiate the N-S auroras and ionospheric loop currents in the auroral zone.

  1. New frontiers in H-Beta auroral photometry

    NASA Astrophysics Data System (ADS)

    Unick, C.; Donovan, E.; Connors, M. G.; Spanswick, E.; Jackel, B. J.; Greffen, M. J.; Wilson, C.; Little, J.; Chaddock, D.; Schofield, I.; MacRae, A.; Chen, S.; Crowther, A.; James, S.; Read, A.; Willis, T.

    2013-12-01

    The proton aurora provides valuable information about magnetotail structure and dynamics. For example, the location of the equatorward boundary of the proton aurora is a robust indicator of magnetotail stretching. Also, proton auroral luminosities combined with in situ ion measurements provide important information about magnetic mapping between the inner CPS and the auroral ionosphere. In this paper, we present a new and innovative proton-auroral (H-Beta) meridian-scanning photometer (MSP) capable of higher spatial and temporal resolution than has been achieved in the past. This H-Beta MSP is the first of a new dual-wavelength (signal/background) MSP design with a single scanning mirror and no other moving parts. The novel filtering architecture allows for a near 100% duty cycle with a 30-second meridian scan and configurable operating modes. The new design is significantly more sensitive than the legacy CANOPUS MSPs. The increased SNR can be employed in a variety of ways, such as to achieve significantly higher time resolution. Here, we present the new instrument design, test data from a commissioning campaign in Athabasca, and some thoughts on how the enhance proton auroral capability can increase the science value of these measurements.

  2. Generation of field-aligned current in the auroral zone

    NASA Technical Reports Server (NTRS)

    Okuda, Hideo

    1991-01-01

    Generation of a magnetic field-aligned current in the auroral zone connecting the magnetospheric and ionospheric plasmas has been studied by means of a three dimensional particle simulation model. The model is of a magnetostatic variety appropriate for a low beta plasma in which the high frequency transverse displacement current has been eliminated. The simulation model is highly elongated along the magnetic field lines in order to model a highly elongated flux tube in the auroral zone. An enhanced field-aligned current was generated by injection of a magnetospheric plasma across the auroral zone magnetic field at the center of the model. Such a plasma injection may correspond to a plasmoid injection at the geomagnetic tail associated with magnetic reconnection during a substorm or a transverse plasma flow along the low latitude magnetopause boundary layer. The results of the simulations show that the field-aligned current can be enhanced over the thermal current by a factor of 5 - 10 via such injection. Associated with the enhanced current are the electrostatic ion cyclotron waves and shear Alfven waves excited in the auroral zone.

  3. Auroral-E Observations: The First Year’s Data.

    DTIC Science & Technology

    1993-02-01

    dipole antenna. The signal was a slow Morse "R." Transmissions were continuous, 24 hours a day. Except for two periods when high winds broke the...incidence-sound- ing (VIS) ionograms . One group, generally called auroral-E, includes nighttime E (par- ticle E) of the k type and E of the r type (Esr

  4. Fractal approach to the description of the auroral region

    SciTech Connect

    Chernyshov, A. A. Mogilevsky, M. M.; Kozelov, B. V.

    2013-07-15

    The plasma of the auroral region, where energetic particles precipitate from the magnetosphere into the ionosphere, is highly inhomogeneous and nonstationary. In this case, traditional methods of classical plasma physics turn out to be inapplicable. In order to correctly describe the dynamic regimes, transition processes, fluctuations, and self-similar scalings in this region, nonlinear dynamics methods based of the concepts of fractal geometry and percolation theory can be used. In this work, the fractal geometry and percolation theory are used to describe the spatial structure of the ionospheric conductivity. The topological properties, fractal dimensions, and connective indices characterizing the structure of the Pedersen and Hall conductivities on the nightside auroral zone are investigated theoretically. The restrictions imposed on the fractal estimates by the condition of ionospheric current percolation are analyzed. It is shown that the fluctuation scalings of the electric fields and auroral glow observed in the auroral zone fit well the restrictions imposed by the critical condition on the percolation of the Pedersen current. Thus, it is demonstrated that the fractal approach is a promising and convenient method for studying the properties of the ionosphere.

  5. Correlations between solar wind parameters and auroral kilometric radiation intensity

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Dangelo, N.

    1981-01-01

    The relationship between solar wind properties and the influx of energy into the nightside auroral region as indicated by the intensity of auroral kilometric radiation is investigated. Smoothed Hawkeye satellite observations of auroral radiation at 178, 100 and 56.2 kHz for days 160 through 365 of 1974 are compared with solar wind data from the composite Solar Wind Plasma Data Set, most of which was supplied by the IMP-8 spacecraft. Correlations are made between smoothed daily averages of solar wind ion density, bulk flow speed, total IMF strength, electric field, solar wind speed in the southward direction, solar wind speed multiplied by total IMF strength, the substorm parameter epsilon and the Kp index. The greatest correlation is found between solar wind bulk flow speed and auroral radiation intensity, with a linear correlation coefficient of 0.78 for the 203 daily averages examined. A possible mechanism for the relationship may be related to the propagation into the nightside magnetosphere of low-frequency long-wavelength electrostatic waves produced in the magnetosheath by the solar wind.

  6. Eyewitness reports of the great auroral storm of 1859

    NASA Astrophysics Data System (ADS)

    Green, James L.; Boardsen, Scott; Odenwald, Sten; Humble, John; Pazamickas, Katherine A.

    2006-01-01

    The great geomagnetic storm of 1859 is really composed of two closely spaced massive worldwide auroral events. The first event began on August 28th and the second began on September 2nd. It is the storm on September 2nd that results from the Carrington-Hodgson white light flare that occurred on the sun September 1st. In addition to published scientific measurements; newspapers, ship logs, and other records of that era provide an untapped wealth of first hand observations giving time and location along with reports of the auroral forms and colors. At its height, the aurora was described as a blood or deep crimson red that was so bright that one "could read a newspaper by". Several important aspects of this great geomagnetic storm are simply phenomenal. Auroral forms of all types and colors were observed to geographic latitudes of 25° and lower. Significant portions of the world's 125,000 miles of telegraph lines were also adversely affected. Many of which were unusable for 8 h or more and had a small but notable economic impact. This paper presents only a select few available first hand accounts of the Great Auroral Event of 1859 in an attempt to give the modern reader a sense of how this spectacular display was received by the public from many places around the globe and present some other important historical aspects of the storm.

  7. Equatorward and poleward expansion of the auroras during auroral substorms

    SciTech Connect

    Nakamura, R. ); Oguti, Takasi ); Yamamoto, Tatsundo ); Kokubun, Susumu )

    1993-04-01

    The authors have used all-sky TV auroral data from a number of different sources to study the formation of the auroral bulge with high spatial and temporal resolution. By linking data sets which cover different parts of the sky they are able to study systematically the development of structures within the poleward expanding bulge. Structures develop to the west, east, and equatorward from a localized region of breakup. To the west a surge develops with a clockwise rotation (when viewed along the magnetic field direction). To the east thin auroral features propagate toward the east. Near the center of the bulge, auroral features develop equatorward, becoming north-south aligned. These and other observations are suggested to be the consequence of the bulge developing along the plasma steamlines as a two cell equipotential distribution. In terms of this model the authors are able to explain the expansions of the bulge in different directions, the observation of pulsating structures in the aurora, and offer explanations of other observations.

  8. Relation of the auroral substorm to the substorm current wedge

    NASA Astrophysics Data System (ADS)

    McPherron, Robert L.; Chu, Xiangning

    2016-12-01

    The auroral substorm is an organized sequence of events seen in the aurora near midnight. It is a manifestation of the magnetospheric substorm which is a disturbance of the magnetosphere brought about by the solar wind transfer of magnetic flux from the dayside to the tail lobes and its return through the plasma sheet to the dayside. The most dramatic feature of the auroral substorm is the sudden brightening and poleward expansion of the aurora. Intimately associated with this expansion is a westward electrical current flowing across the bulge of expanding aurora. This current is fed by a downward field-aligned current (FAC) at its eastern edge and an upward current at its western edge. This current system is called the substorm current wedge (SCW). The SCW forms within a minute of auroral expansion. FAC are created by pressure gradients and field line bending from shears in plasma flow. Both of these are the result of pileup and diversion of plasma flows in the near-earth plasma sheet. The origins of these flows are reconnection sites further back in the tail. The auroral expansion can be explained by a combination of a change in field line mapping caused by the substorm current wedge and a tailward growth of the outer edge of the pileup region. We illustrate this scenario with a complex substorm and discuss some of the problems associated with this interpretation.

  9. A Rocket-Base Study of Auroral Electrodynamics Within the Current Closure Ionosphere

    NASA Technical Reports Server (NTRS)

    Kaeppler, Stephen R.; Kletzing, Craig; Bounds, Scott R.; Sigsbee, Kristine M.; Gjerloev, Jesper W.; Anderson, Brian Jay; Korth, Haje; Lessard, Marc; Labelle, James W.; Dombrowski, Micah P.; Pfaff, Robert F.; Rowland, Douglas E.; Jones, Sarah; Heinselman, Craig J.; DudokdeWit, Thierry

    2011-01-01

    The Auroral Current and Electrodynamics Structure (ACES) mission consisted of two sounding rockets launched nearly simultaneously from Poker Flat Research Range, AK on January 29, 2009 into a dynamic multiple-arc aurora. The ACES rocket mission, in conjunction with the PFISR Radar, was designed to observe the three-dimensional current system of a stable auroral arc system. ACES utilized two well instrumented payloads flown along very similar magnetic field footprints, at various altitudes with small temporal separation between both payloads. ACES High, the higher altitude payload (apogee 360 km), took in-situ measurements of the plasma parameters above the current closure region to provide the input signature into the lower ionosphere. ACES Low, the low-altitude payload (apogee 130 km), took similar observations within the current closure region, where cross-field currents can flow. We present results comparing observations of the electric fields, magnetic fields, electron flux, and the electron temperature at similar magnetic footpoints between both payloads. We further present data from all-sky imagers and PFISR detailing the evolution of the auroral event as the payloads traversed regions connected by similar magnetic footpoints. Current measurements derived from the magnetometers on both payloads are further compared. We examine data from both PFISR and observations on the high-altitude payload which we interpreted as a signature of electron acceleration by means of Alfv n waves. We further examine all measurements to understand ionospheric conductivity and how energy is being deposited into the ionosphere through Joule heating. Data from ACES is compared against models of Joule heating to make inferences regarding the effect of collisions at various altitudes.

  10. Strong Magnetic Field Fluctuations within Filamentary Auroral Density Cavities Interpreted as VLF Saucer Sources

    NASA Technical Reports Server (NTRS)

    Knudsen, D. L.; Kabirzadeh, R.; Burchill, J. K.; Pfaff, Robert F.; Wallis, D. D.; Bounds, S. R.; Clemmons, J. H.; Pincon, J.-L.

    2012-01-01

    The Geoelectrodynamics and Electro-Optical Detection of Electron and SuprathermalIon Currents (GEODESIC) sounding rocket encountered more than 100 filamentary densitycavities associated with enhanced plasma waves at ELF (3 kHz) and VLF (310 kHz)frequencies and at altitudes of 800990 km during an auroral substorm. These cavities weresimilar in size (20 m diameter in most cases) to so-called lower-hybrid cavities (LHCs)observed by previous sounding rockets and satellites; however, in contrast, many of theGEODESIC cavities exhibited up to tenfold enhancements in magnetic wave powerthroughout the VLF band. GEODESIC also observed enhancements of ELF and VLFelectric fields both parallel and perpendicular to the geomagnetic field B0 within cavities,though the VLF E field increases were often not as large proportionally as seen in themagnetic fields. This behavior is opposite to that predicted by previously published theoriesof LHCs based on passive scattering of externally incident auroral hiss. We argue thatthe GEODESIC cavities are active wave generation sites capable of radiating VLF wavesinto the surrounding plasma and producing VLF saucers, with energy supplied by cold,upward flowing electron beams composing the auroral return current. This interpretation issupported by the observation that the most intense waves, both inside and outside cavities,occurred in regions where energetic electron precipitation was largely inhibited orabsent altogether. We suggest that the wave-enhanced cavities encountered by GEODESICwere qualitatively different from those observed by earlier spacecraft because of thefortuitous timing of the GEODESIC launch, which placed the payload at apogee within asubstorm-related return current during its most intense phase, lasting only a few minutes.

  11. Nonlinear interactions of electromagnetic waves with the auroral ionosphere

    SciTech Connect

    Wong, Alfred Y.

    1999-09-20

    The ionosphere provides us with an opportunity to perform plasma experiments in an environment with long confinement times, very large-scale lengths, and no confining walls. The auroral ionosphere with its nearly vertical magnetic field geometry is uniquely endowed with large amount of free energy from electron and ion precipitation along the magnetic field and mega-ampere current across the magnetic field. To take advantage of this giant outdoor laboratory, two facilities HAARP and HIPAS, with frequencies ranging from the radio to optical bands, are now available for active probing of and interaction with this interesting region. The ponderomotive pressures from the self-consistent wave fields have produced significant local perturbations of density and particle distributions at heights where the incident EM frequency matches a plasma resonance. This paper will review theory and experiments covering the nonlinear phenomena of parametric decay instability to wave collapse processes. At HF frequencies plasma lenses can be created by preconditioning pulses to focus what is a normally divergent beam into a high-intensity spot to further enhance nonlinear phenomena. At optical wavelengths a large rotating liquid metal mirror is used to focus laser pulses up to a given height. Such laser pulses are tuned to the same wavelengths of selected atomic and molecular resonances, with resulting large scattering cross sections. Ongoing experiments on dual-site experiments and excitation of ELF waves will be presented. The connection of such basic studies to environmental applications will be discussed. Such applications include the global communication using ELF waves, the ozone depletion and remediation and the control of atmospheric CO{sub 2} through the use of ion cyclotron resonant heating.

  12. The Large-Scale Current System During Auroral Substorms

    NASA Astrophysics Data System (ADS)

    Gjerloev, Jesper

    2015-04-01

    The substorm process has been discussed for more than four decades and new empirical large-scale models continue to be published. The continued activity implies both the importance and the complexity of the problem. We recently published a new model of the large-scale substorm current system (Gjerloev and Hoffman, JGR, 2014). Based on data from >100 ground magnetometers (obtained from SuperMAG), 116 isolated substorms, global auroral images (obtained by the Polar VIS Earth Camera) and a careful normalization technique we derived an empirical model of the ionospheric equivalent current system. Our model yield some unexpected features that appear inconsistent with the classical single current wedge current system. One of these features is a distinct latitudinal shift of the westward electrojet (WEJ) current between the pre- and post-midnight region and we find evidence that these two WEJ regions are quasi disconnected. This, and other observational facts, led us to propose a modified 3D current system configuration that consists of 2 wedge type systems: a current wedge in the pre-midnight region (bulge current wedge), and another current wedge system in the post-midnight region (oval current wedge). The two wedge systems are shifted in latitude but overlap in local time in the midnight region. Our model is at considerable variance with previous global models and conceptual schematics of the large-scale substorm current system. We speculate that the data coverage, the methodologies and the techniques used in these previous global studies are the cause of the differences in solutions. In this presentation we present our model, compare with other published models and discuss possible causes for the differences.

  13. Nonlinear interactions of electromagnetic waves with the auroral ionosphere

    NASA Astrophysics Data System (ADS)

    Wong, Alfred Y.

    1999-09-01

    The ionosphere provides us with an opportunity to perform plasma experiments in an environment with long confinement times, very large-scale lengths, and no confining walls. The auroral ionosphere with its nearly vertical magnetic field geometry is uniquely endowed with large amount of free energy from electron and ion precipitation along the magnetic field and mega-ampere current across the magnetic field. To take advantage of this giant outdoor laboratory, two facilities HAARP and HIPAS, with frequencies ranging from the radio to optical bands, are now available for active probing of and interaction with this interesting region. The ponderomotive pressures from the self-consistent wave fields have produced significant local perturbations of density and particle distributions at heights where the incident EM frequency matches a plasma resonance. This paper will review theory and experiments covering the nonlinear phenomena of parametric decay instability to wave collapse processes. At HF frequencies plasma lenses can be created by preconditioning pulses to focus what is a normally divergent beam into a high-intensity spot to further enhance nonlinear phenomena. At optical wavelengths a large rotating liquid metal mirror is used to focus laser pulses up to a given height. Such laser pulses are tuned to the same wavelengths of selected atomic and molecular resonances, with resulting large scattering cross sections. Ongoing experiments on dual-site experiments and excitation of ELF waves will be presented. The connection of such basic studies to environmental applications will be discussed. Such applications include the global communication using ELF waves, the ozone depletion and remediation and the control of atmospheric CO2 through the use of ion cyclotron resonant heating.

  14. Activities at the Smart Structures Research Institute

    NASA Astrophysics Data System (ADS)

    Gardiner, Peter T.

    1991-12-01

    Smart Structures and Materials technology will undoubtedly yield a wide range of new materials plus new sensing and actuation technologies and this will have a radical effect on current approaches to structural design. To meet the multi-disciplinary research challenge posed by this technology, the Smart Structures Research Institute (SSRI) has been established at the University of Strathclyde, Glasgow. This paper describes the background, current and planned activities and progress made in developing this new and very promising technology.

  15. Relationship of Topside Ionospheric Ion Outflows to Auroral Forms and Precipitations, Plasma Waves, and Convection Observed by POLAR

    NASA Technical Reports Server (NTRS)

    Hirahara, M.; Horwitz, J. L.; Moore, T. E.; Germany, G. A.; Spann, J. F.; Peterson, W. K.; Shelley, E. G.; Chandler, M. O.; Giles, B. L.; Craven, P. D.; Pollock, C. J.; Gurnett, D. A.; Persoon, A. M.; Scudder, J. D.; Maynard, N. C.; Mozer, F. S.; Brittnacher, M. J.; Nagai, T.

    1997-01-01

    The POLAR satellite often observes upflowing ionospheric ions (UFls) in and near the auroral oval on southern perigee (approximately 5000 km altitude) passes. We present the UFI features observed by the thermal ion dynamics experiment (TIDE) and the toroidal imaging mass-angle spectrograph (TIMAS) in the dusk-dawn sector under two different geomagnetic activity conditions in order to elicit their relationships with auroral forms, wave emissions, and convection pattern from additional POLAR instruments. During the active interval, the ultraviolet imager (UVI) observed a bright discrete aurora on the dusk side after the substorm onset and then observed a small isolated aurora form and diffuse auroras on the dawn side during the recovery phase. The UFls showed clear conic distributions when the plasma wave instrument (PWI) detected strong broadband wave emissions below approximately 10 kHz, while no significant auroral activities were observed by UVI. At higher latitudes, the low-energy UFI conics gradually changed to the polar wind component with decreasing intensity of the broadband emissions. V-shaped auroral kilometric radiation (AKR) signatures observed above approximately 200 kHz by PWI coincided with the region where the discrete aurora and the UFI beams were detected. The latitude of these features was lower than that of the UFI conics. During the observations of the UFI beams and conics, the lower-frequency fluctuations observed by the electric field instrument (EFI) were also enhanced, and the convection directions exhibited large fluctuations. It is evident that large electrostatic potential drops produced the precipitating electrons and discrete auroras, the UFI beams, and the AKR, which is also supported by the energetic plasma data from HYDRA. Since the intense broadband emissions were also observed with the UFIs. the ionospheric ions could be energized transversely before or during the parallel acceleration due to the potential drops.

  16. Three-station measurements of upward vertical wind associated with auroral precipitation.

    NASA Astrophysics Data System (ADS)

    Hampton, D. L.; Meriwether, J. W.; Conde, M.

    2014-12-01

    Sustained F-region thermospheric upward vertical winds associated with auroral precipitation were observed by a dedicated Fabry-Perot interferometer observing the OI emission at 630.0 nm at Poker Flat Research Range from 2009 to 2011. The winds are typically 20 to 40 m/s and lasted for the duration of low-energy electron precipitation. Based on these observations we have initiated a three-station campaign to further investigate the relative local time and latitudinal extent of these winds. The three stations are located at Poker Flat Research Range (65.1 N, -147.4 E), Eagle, AK (64.8 N, -141.2 E) and Fort Yukon, AK (66.6 N, -145.2 E). All three stations operated simultaneously from Feb to April of 2014 . We will present initial results from the season especially the correlation between the observed vertical motion and the location and intensity of auroral precipitation as measured by co-located cameras and spectrographs.

  17. An overview of Japanese CELSS research activities.

    PubMed

    Nitta, K

    1987-01-01

    Many research activities regarding Controlled Ecological Life Support System (CELSS) have been conducted and continued all over the world since the 1960's and the concept of CELSS is now changing from Science Fiction to Scientific Reality. Development of CELSS technology is inevitable for future long duration stays of human beings in space, for lunar base construction and for manned mars flight programs. CELSS functions can be divided into two categories, Environment Control and Material Recycling. Temperature, humidity, total atmospheric pressure and partial pressure of oxygen and carbon dioxide, necessary for all living things, are to be controlled by the environment control function. This function can be performed by technologies already developed and used as the Environment Control Life Support System (ECLSS) of Space Shuttle and Space Station. As for material recycling, matured technologies have not yet been established for fully satisfying the specific metabolic requirements of each living thing including human beings. Therefore, research activities for establishing CELSS technology should be focused on material recycling technologies using biological systems such as plants and animals and physico-chemical systems, for example, a gas recycling system, a water purifying and recycling system and a waste management system. Based on these considerations, Japanese research activities have been conducted and will be continued under the tentative guideline of CELSS research activities as shown in documents /1/, /2/. The status of the over all activities are discussed in this paper.

  18. An overview of Japanese CELSS research activities

    NASA Astrophysics Data System (ADS)

    Nitta, Keiji

    Many research activities regarding Controlled Ecological Life Support System (CELSS) have been conducted and continued all over the world since the 1960's and the concept of CELSS is now changing from Science Fiction to Scientific Reality. Development of CELSS technology is inevitable for future long duration stays of human beings in space, for lunar base construction and for manned mars flight programs. CELSS functions can be divided into two categories, Environment Control and Material Recycling. Temperature, humidity, total atmospheric pressure and partial pressure of oxygen and carbon dioxide, necessary for all living things, are to be controlled by the environment control function. This function can be performed by technologies already developed and used as the Environment Control Life Support System (ECLSS) of Space Shuttle and Space Station. As for material recycling, matured technologies have not yet been established for fully satisfying the specific metabolic requirements of each living thing including human beings. Therefore, research activities for establishing CELSS technology should be focused on material recycling technologies using biological systems such as plants and animals and physico-chemical systems, for example, a gas recycling system, a water purifying and recycling system and a waste management system. Based on these considerations, Japanese research activities have been conducted and will be continued under the tentative guideline of CELSS research activities as shown in documents /1/,/2/. The status of the over all activities are discussed in this paper.

  19. Characteristics of Poker Flat Incoherent Scatter Radar (PFISR) naturally enhanced ion-acoustic lines (NEIALs) in relation to auroral forms

    NASA Astrophysics Data System (ADS)

    Michell, R. G.; Grydeland, T.; Samara, M.

    2014-10-01

    Naturally enhanced ion-acoustic lines (NEIALs) have been observed with the Poker Flat Incoherent Scatter Radar (PFISR) ever since it began operating in 2006. The nearly continuous operation of PFISR since then has led to a large number of NEIAL observations from there, where common-volume, high-resolution auroral imaging data are available. We aim to systematically distinguish the different types of auroral forms that are associated with different NEIAL features, including spectral shape and altitude extent. We believe that NEIALs occur with a continuum of morphological characteristics, although we find that most NEIALs observed with PFISR fall into two general categories. The first group occurs at fairly low altitudes - F region or below - and have power at, and spread between, the ion-acoustic peaks. The second group contains the type of NEIALs that have previously been observed with the EISCAT radars, those that extend to high altitudes (600 km or more) and often have large asymmetries in the power enhancements between the two ion-acoustic shoulders. We find that there is a correlation between the auroral structures and the type of NEIALs observed, and that the auroral structures present during NEIAL events are consistent with the likely NEIAL generation mechanisms inferred in each case. The first type of NEIAL - low altitude - is the most commonly observed with PFISR and is most often associated with active, structured auroral arcs, such as substorm growth phase, and onset arcs and are likely generated by Langmuir turbulence. The second type of NEIAL - high altitude - occurs less frequently in the PFISR radar and is associated with aurora that contains large fluxes of low-energy electrons, as can happen in poleward boundary intensifications as well as at substorm onset and is likely the result of current-driven instabilities and in some cases Langmuir turbulence as well. In addition, a preliminary auroral photometry analysis revealed that there is an

  20. Research and technology activities at Ames Research Center's Biomedical Research Division

    NASA Technical Reports Server (NTRS)

    Martello, N.

    1985-01-01

    Various research and technology activities at Ames Research Center's Biomedical Research Division are described. Contributions to the Space Administration's goals in the life sciences include descriptions of research in operational medicine, cardiovascular deconditioning, motion sickness, bone alterations, muscle atrophy, fluid and electrolyte changes, radiation effects and protection, behavior and performance, gravitational biology, and life sciences flight experiments.

  1. Auroras Now! - Auroral nowcasting service for Hotels in Finnish Lapland and its performance during winter 2003-2004

    NASA Astrophysics Data System (ADS)

    Kauristie, K.; Mälkki, A.; Pulkkinen, A.; Nevanlinna, H.; Ketola, A.; Tulkki, V.; Raita, T.; Blanco, A.

    2004-12-01

    European Space Agency is currently supporting 17 Service Development Activities (SDA) within its Space Weather Pilot Project. Auroras Now!, one of the SDAs, has been operated during November 2003 - March 2004 as its pilot season. The service includes a public part freely accessible in Internet (http://aurora.fmi.fi) and a private part visible only to the customers of two hotels in the Finnish Lapland through the hotels' internal TV-systems. The nowcasting system is based on the magnetic recordings of two geophysical observatories, Sodankylä (SOD, MLAT ~64 N) and Nurmijärvi (NUR, MLAT ~57 N). The probability of auroral occurrence is continuously characterised with an empirically determined three-level scale. The index is updated once per hour and based on the magnetic field variations recorded at the observatories. During dark hours the near-real time auroral images acquired at SOD are displayed. The hotel service also includes cloudiness predictions for the coming night. During the pilot season the reliability of the three-level magnetic alarm system was weekly evaluated by comparing its prediction with auroral observations by the nearby all-sky camera. Successful hits and failures were scored according to predetermined rules. The highest credit points when it managed to spot auroras in a timely manner and predict their brightness correctly. Maximum penalty points were given when the alarm missed clear bright auroras lasting for more than one hour. In this presentation we analyse the results of the evaluation, present some ideas to further sharpen the procedure, and discuss more generally the correlation between local auroral and magnetic activity.

  2. Electrodynamic parameters in the nighttime sector during auroral substorms

    NASA Technical Reports Server (NTRS)

    Fujii, R.; Hoffman, R. A.; Anderson, P. C.; Craven, J. D.; Sugiura, M.; Frank, L. A.; Maynard, N. C.

    1994-01-01

    The characteristics of the large-scale electrodynamic parameters, field-aligned currents (FACs), electric fields, and electron precipitation, which are associated with auroral substorm events in the nighttime sector, have been obtained through a unique analysis which places the ionospheric measurements of these parameters into the context of a generic substorm determined from global auroral images. A generic bulge-type auroral emission region has been deduced from auroral images taken by the Dynamics Explorer 1 (DE 1) satellite during a number of isolated substorms, and the form has been divided into six sectors, based on the peculiar emission characteristics in each sector: west of bulge, surge horn, surge, middle surge, eastern bulge, and east of bulge. By comparing the location of passes of the Dynamics Explorer 2 (DE 2) satellite to the simultaneously obtained auroral images, each pass is placed onto the generic aurora. The organization of DE 2 data in this way has systematically clarified peculiar characteristics in the electrodynamic parameters. An upward net current mainly appears in the surge, with little net current in the surge horn and the west of bulge. The downward net current is distributed over wide longitudinal regions from the eastern bulge to the east of bulge. Near the poleward boundary of the expanding auroral bulge, a pair of oppositely directed FAC sheets is observed, with the downward FAC on the poleward side. This downward FAC and most of the upward FAC in the surge and the middle surge are assoc iated with narrow, intense antisunwqard convection, corresponding to an equatorward directed spikelike electric field. This pair of currents decreases in amplitude and latitudinal width toward dusk in the surge and the west of bulge, and the region 1 and 2 FACs become embedded in the sunward convection region. The upward FAC region associated with the spikelike field on the poleward edge of the bulge coincides well with intense electron

  3. Auroral and sub-auroral interaction at the F-region ionosphere. Final report, 1 June 1987-30 June 1989

    SciTech Connect

    Aarons, J.; Mendillo, M.

    1989-08-31

    Deterioration of satellite signals and fading on HF are results of the appearance of intense irregularities of the order of meters to several hundred meters in the F layer. At auroral and sub-auroral latitudes, the irregularities become intense and create serious problems. The interaction of the ionosphere during magnetic storms has been studied at auroral and subauroral latitudes. Results include a model which shows the expansion during the injection phase of the magnetic storm and the effect of storm effects of the stored-up energy in the ring current during the recovery phase. In comparing observations with incoherent scatter data from Millstone Hill the total convection velocity appears to be the dominating parameter in the injection-phase creation of irregularities. This work will move to studying the global effects of individual storms since the storms can inhibit irregularities at the equator while creating them at auroral and sub-auroral latitudes.

  4. In-situ observation of electron kappa distributions associated with discrete auroral arcs

    NASA Astrophysics Data System (ADS)

    Ogasawara, Keiichi; Livadiotis, George; Samara, Marilia; Michell, Robert; Grubbs, Guy

    2016-04-01

    The Medium-energy Electron SPectrometer (MESP) sensor aboard a NASA sounding rocket was launched from Poker Flat Research Range on 3 March 2014 as a part of Ground-to-Rocket Electrodynamics-Electrons Correlative Experiment (GREECE) mission. GREECE targeted to discover convergent E-field structures at low altitude ionosphere to find their contribution to the rapid fluid-like structures of aurora, and MESP successfully measured the precipitating electrons from 2 to 200 keV within multiple discrete auroral arcs with the apogee of 350 km. MESP's unprecedented electron energy acceptance and high geometric factor made it possible to investigate precise populations of the suprathermal components measured in the inverted-V type electron energy distributions. The feature of these suprathermal electrons are explained by the kappa distribution functions with the parameters (densty, temperature, and kappa) consistent with the near-Earth tail plasma sheet, suggesting the source population of the auroral electrons. The kappa-values are different between each arc observed as a function of latitude, but are almost stable within one discrete arc. We suggest that this transition of kappa reflects the probagation history of source electrons through the plasma sheet by changing its state from non-equilibrium electron distributions to thermal ones.

  5. Development and performance of a suprathermal electron spectrometer to study auroral precipitations

    NASA Astrophysics Data System (ADS)

    Ogasawara, Keiichi; Grubbs, Guy; Michell, Robert G.; Samara, Marilia; Stange, Jason L.; Trevino, John A.; Webster, James; Jahn, Jörg-Micha

    2016-05-01

    The design, development, and performance of Medium-energy Electron SPectrometer (MESP), dedicated to the in situ observation of suprathermal electrons in the auroral ionosphere, are summarized in this paper. MESP employs a permanent magnet filter with a light tight structure to select electrons with proper energies guided to the detectors. A combination of two avalanche photodiodes and a large area solid-state detector (SSD) provided 46 total energy bins (1 keV resolution for 3-20 keV range for APDs, and 7 keV resolution for >20 keV range for SSDs). Multi-channel ultra-low power application-specific integrated circuits are also verified for the flight operation to read-out and analyze the detector signals. MESP was launched from Poker Flat Research Range on 3 March 2014 as a part of ground-to-rocket electrodynamics-electrons correlative experiment (GREECE) mission. MESP successfully measured the precipitating electrons from 3 to 120 keV in 120-ms time resolution and characterized the features of suprathermal distributions associated with auroral arcs throughout the flight. The measured electrons were showing the inverted-V type spectra, consistent with the past measurements. In addition, investigations of the suprathermal electron population indicated the existence of the energetic non-thermal distribution corresponding to the brightest aurora.

  6. Development and performance of a suprathermal electron spectrometer to study auroral precipitations.

    PubMed

    Ogasawara, Keiichi; Grubbs, Guy; Michell, Robert G; Samara, Marilia; Stange, Jason L; Trevino, John A; Webster, James; Jahn, Jörg-Micha

    2016-05-01

    The design, development, and performance of Medium-energy Electron SPectrometer (MESP), dedicated to the in situ observation of suprathermal electrons in the auroral ionosphere, are summarized in this paper. MESP employs a permanent magnet filter with a light tight structure to select electrons with proper energies guided to the detectors. A combination of two avalanche photodiodes and a large area solid-state detector (SSD) provided 46 total energy bins (1 keV resolution for 3-20 keV range for APDs, and 7 keV resolution for >20 keV range for SSDs). Multi-channel ultra-low power application-specific integrated circuits are also verified for the flight operation to read-out and analyze the detector signals. MESP was launched from Poker Flat Research Range on 3 March 2014 as a part of ground-to-rocket electrodynamics-electrons correlative experiment (GREECE) mission. MESP successfully measured the precipitating electrons from 3 to 120 keV in 120-ms time resolution and characterized the features of suprathermal distributions associated with auroral arcs throughout the flight. The measured electrons were showing the inverted-V type spectra, consistent with the past measurements. In addition, investigations of the suprathermal electron population indicated the existence of the energetic non-thermal distribution corresponding to the brightest aurora.

  7. The 30 MHz imaging radar observations of auroral irregularities during the JOULE campaign

    NASA Astrophysics Data System (ADS)

    Bahcivan, H.; Hysell, D. L.; Larsen, M. F.; Pfaff, R. F.

    2005-05-01

    Coherent backscatter from the auroral electrojet was observed by a 30 MHz imaging radar in Anchorage during the Joint Observations of Upper Latitude Electrodynamics (JOULE) campaign conducted from the Poker Flat Research Range in the spring of 2003. The observations were made at the same time that ionospheric electric fields and plasma number densities were measured in situ by instruments on sounding rockets. Neutral wind profiles were also measured during the campaign from triangulation of chemiluminescent trails from rocket releases. Aperture synthesis radar imaging techniques permit the sorting of the coherent backscatter into small azimuth and range bins and the determination of the scattering altitude. Individual Doppler spectra could thereby be unambiguously associated with in situ electric field measurements in the same small volume. We find that the Doppler shifts of the auroral echoes correspond to the ion acoustic speed times the cosine of the flow angle, where the former is predicted according to an empirical wave heating law. Type I echoes are only observed for very small flow angles regardless of the convection speed.

  8. Research to Practice: Implementing Physical Activity Recommendations

    PubMed Central

    Davis, Sally M.; Cruz, Theresa H.; Kozoll, Richard

    2016-01-01

    Introduction Dissemination and implementation (D&I) science focuses on bridging the gap between research and practice. The Community Preventive Services Task Force (CPSTF) published recommendations for increasing physical activity based on scientific review and consensus. Little research on the D&I of these recommendations has been conducted in under-represented populations at high risk for inactivity and chronic disease. Methods Partnering with one rural community (beta site), the University of New Mexico Prevention Research Center studied the translation of CPSTF recommendations to practice. Strategies for increasing physical activity were selected, implemented, and analyzed in 2009 to 2013. Participant observations; content analysis of meeting minutes, field notes, and other documents; and in-depth interviews were conducted over the 5-year period to identify factors important for carrying out the CPSTF recommendations for physical activity in a rural New Mexico community. Results Included among the implementation outcomes were new sidewalks and trails, a community-wide campaign, social support of walking, and park improvements. The following factors were identified as important to the implementation process: an active community-academic partnership; multiple partners; culturally appropriate strategies; and approaches that fit local context and place characteristics (topography, land ownership, population clusters, existing roadways). Conclusions This study illustrates how evidence can be translated to practice and identifies key factors in that process. The successful beta model provides a practical blueprint for D&I in rural, under-represented populations. This model is currently being disseminated (scaled up) to other rural New Mexico communities. PMID:28215385

  9. On the formation and origin of substorm growth phase/onset auroral arcs inferred from conjugate space-ground observations

    DOE PAGES

    Motoba, T.; Ohtani, S.; Anderson, B. J.; ...

    2015-10-27

    In this study, magnetotail processes and structures related to substorm growth phase/onset auroral arcs remain poorly understood mostly due to the lack of adequate observations. In this study we make a comparison between ground-based optical measurements of the premidnight growth phase/onset arcs at subauroral latitudes and magnetically conjugate measurements made by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) at ~780 km in altitude and by the Van Allen Probe B (RBSP-B) spacecraft crossing L values of ~5.0–5.6 in the premidnight inner tail region. The conjugate observations offer a unique opportunity to examine the detailed features of the arcmore » location relative to large-scale Birkeland currents and of the magnetospheric counterpart. Our main findings include (1) at the early stage of the growth phase the quiet auroral arc emerged ~4.3° equatorward of the boundary between the downward Region 2 (R2) and upward Region 1 (R1) currents; (2) shortly before the auroral breakup (poleward auroral expansion) the latitudinal separation between the arc and the R1/R2 demarcation narrowed to ~1.0°; (3) RBSP-B observed a magnetic field signature of a local upward field-aligned current (FAC) connecting the arc with the near-Earth tail when the spacecraft footprint was very close to the arc; and (4) the upward FAC signature was located on the tailward side of a local plasma pressure increase confined near L ~5.2–5.4. These findings strongly suggest that the premidnight arc is connected to highly localized pressure gradients embedded in the near-tail R2 source region via the local upward FAC.« less

  10. On the formation and origin of substorm growth phase/onset auroral arcs inferred from conjugate space-ground observations

    SciTech Connect

    Motoba, T.; Ohtani, S.; Anderson, B. J.; Korth, H.; Mitchell, D.; Lanzerotti, L. J.; Shiokawa, K.; Connors, M.; Kletzing, C. A.; Reeves, G. D.

    2015-10-27

    In this study, magnetotail processes and structures related to substorm growth phase/onset auroral arcs remain poorly understood mostly due to the lack of adequate observations. In this study we make a comparison between ground-based optical measurements of the premidnight growth phase/onset arcs at subauroral latitudes and magnetically conjugate measurements made by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) at ~780 km in altitude and by the Van Allen Probe B (RBSP-B) spacecraft crossing L values of ~5.0–5.6 in the premidnight inner tail region. The conjugate observations offer a unique opportunity to examine the detailed features of the arc location relative to large-scale Birkeland currents and of the magnetospheric counterpart. Our main findings include (1) at the early stage of the growth phase the quiet auroral arc emerged ~4.3° equatorward of the boundary between the downward Region 2 (R2) and upward Region 1 (R1) currents; (2) shortly before the auroral breakup (poleward auroral expansion) the latitudinal separation between the arc and the R1/R2 demarcation narrowed to ~1.0°; (3) RBSP-B observed a magnetic field signature of a local upward field-aligned current (FAC) connecting the arc with the near-Earth tail when the spacecraft footprint was very close to the arc; and (4) the upward FAC signature was located on the tailward side of a local plasma pressure increase confined near L ~5.2–5.4. These findings strongly suggest that the premidnight arc is connected to highly localized pressure gradients embedded in the near-tail R2 source region via the local upward FAC.

  11. Observations of vertical winds and the origin of thermospheric gravity waves launched by auroral substorms and westward travelling surges

    NASA Technical Reports Server (NTRS)

    Rees, D.

    1986-01-01

    Several sequences of observations of strong vertical winds in the upper thermosphere are discussed, in conjunction with models of the generation of such winds. In the auroral oval, the strongest upward winds are observed in or close to regions of intense auroral precipitation and strong ionospheric currents. The strongest winds, of the order of 100 to 200 m/sec are usually upward, and are both localized and of relatively short duration (10 to 20 min). In regions adjacent to those displaying strong upward winds, and following periods of upward winds, downward winds of rather lower magnitude (40 to about 80 m/sec) may be observed. Strong and rapid changes of horizontal winds are correlated with these rapid vertical wind variations. Considered from a large scale viewpoint, this class of strongly time dependent winds propagate globally, and may be considered to be gravity waves launched from an auroral source. During periods of very disturbed geomagnetic activity, there may be regions within and close to the auroral oval where systematic vertical winds of the order of 50 m/sec will occur for periods of several hours. Such persistent winds are part of a very strong large scale horizontal wind circulation set up in the polar regions during a major geomagnetic disturbance. This second class of strong horizontal and vertical winds corresponds more to a standing wave than to a gravity wave, and it is not as effective as the first class in generating large scale propagating gravity waves and correlated horizontal and vertical oscillations. A third class of significant (10 to 30 m/sec) vertical winds can be associated with systematic features of the average geomagnetic energy and momentum input to the polar thermosphere, and appear in statistical studies of the average vertical wind as a function of Universal Time at a given location.

  12. Alaskan Auroral All-Sky Images on the World Wide Web

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.

    1997-01-01

    In response to a 1995 NASA SPDS announcement of support for preservation and distribution of important data sets online, the Geophysical Institute, University of Alaska Fairbanks, Alaska, proposed to provide World Wide Web access to the Poker Flat Auroral All-sky Camera images in real time. The Poker auroral all-sky camera is located in the Davis Science Operation Center at Poker Flat Rocket Range about 30 miles north-east of Fairbanks, Alaska, and is connected, through a microwave link, with the Geophysical Institute where we maintain the data base linked to the Web. To protect the low light-level all-sky TV camera from damage due to excessive light, we only operate during the winter season when the moon is down. The camera and data acquisition is now fully computer controlled. Digital images are transmitted each minute to the Web linked data base where the data are available in a number of different presentations: (1) Individual JPEG compressed images (1 minute resolution); (2) Time lapse MPEG movie of the stored images; and (3) A meridional plot of the entire night activity.

  13. Stability of Alfvén eigenmodes in the vicinity of auroral arc

    NASA Astrophysics Data System (ADS)

    Hiraki, Yasutaka

    2013-08-01

    The purpose of this study is to give a theoretical suggestion to the essential question why east-west elongated auroral arc can keep its anisotropic structure for a long time. It could be related to the stability of east-westward traveling modes in the vicinity of arc, which may develop into wavy or spiral structures, whereas north-southward modes are related to splitting of arcs. Taking into account the arc-inducing field-aligned current and magnetic shears, we examine changes in the stability of Alfvén eigenmodes that are coupled to perpendicular modes in the presence of convection electric field. It is demonstrated that the poleward current shear suppresses growth of the westward mode in case of the westward convection electric field. Only the poleward mode is still unstable because of the properties of feedback shear waves. It is suggested that this tends to promote (poleward) arc splitting as often observed during quiet times. We further draw a diagram of the westward mode growth rate as a function of convection electric field and current shear, evaluating critical fields for instabilities of lower Alfvén harmonics. It is discovered that a switching phenomenon of fast-growing mode from fundamental to the first harmonic occurs for a high electric field regime. Our stability criterion is applied to some observed situations of auroral arc current system during pre-breakup active times.

  14. [Aurore, child martyr. Essay on violence done to children].

    PubMed

    Gaudreau, J

    1992-01-01

    This article draws on the sad story of Aurore Gagnon, a battered child raised in rural Québec and whose turmoil was dramatized on film. By elaborating on this symbol, the author is able to generate, at least in a systemic perspective, a number of issues and outlooks that go far beyond the generalities usually associated with this tale. For instance, there is ample evidence showing that the behaviour of Aurore's stepmother, aberrant as it may be, is largely caused by a set of environmental circumstances. Of course, today's social conditions hardly resemble those of the past. Yet, given the conjunctions of certain factors, children, who are nevertheless our most valuable asset, continue to be in danger in the presence of their very own parents.

  15. Auroral spectral estimation with wide-band color mosaic CCDs

    NASA Astrophysics Data System (ADS)

    Jackel, B. J.; Unick, C.; Syrjäsuo, M. T.; Partamies, N.; Wild, J. A.; Woodfield, E. E.; McWhirter, I.; Kendall, E.; Spanswick, E.

    2013-12-01

    Color mosaic CCDs use a matrix of different wide-band micro-filters in order to produce images with several (often three) color channels. These devices are increasingly employed in auroral studies to provide time sequences of two dimensional luminosity maps, but the color information is typically only used for qualitative analysis. In this study we use Backus-Gilbert linear inversion techniques to obtain quantitative measures of effective spectral resolution for multi-channel color mosaic CCDs. These techniques also allow us to explore the possibility of further improvements by modifying or combining multiple detectors. We consider two spectrally calibrated commercial color CCDs (Sony ICX285AQ and ICX429AKL) in order to determine effective wavelength resolution of each device individually, together, and with additional filters. From these results we develop methods to enhance the utility of existing data sets, and propose ways to improve the next generation of low-cost color auroral imaging systems.

  16. A simple kinetic theory of auroral arc scales

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.

    1986-01-01

    A kinetic theory of the origins of the auroral arc scale spectrum is presented in this paper. The conceptual basis of the theory is current conservation in a turbulent plasma at the magnetospheric equatorial region in which a field-aligned current is generated and the local electrostatic potential structure is forced to adjust to the presence of the field-aligned current. This simple model uses an ad hoc Ohm's law relationship between the perpendicular current and the perpendicular electric field, but with a negative conductance in the generator region so that J(perpendicular) x E(perpendicular) is less than 0. An exact solution of a simple model of the concept yields a bistatic auroral generator for which multiple-arc formation is predicted if the field-aligned current exceeds a critical value. The predicted scale spectrum is inversely proportional to the square root of the field-aligned current strength spectrum.

  17. Inferences Concerning the Magnetospheric Source Region for Auroral Breakup

    NASA Technical Reports Server (NTRS)

    Lyons, L. R.

    1992-01-01

    It is argued that the magnetospheric source region for auroral arc breakup and substorm initiation is along boundary plasma sheet (BPS) magnetic field lines. This source region lies beyond a distinct central plasma sheet (CPS) region and sufficiently far from the Earth that energetic ion motion violates the guiding center approximation (i.e., is chaotic). The source region is not constrained to any particular range of distances from the Earth, and substorm initiation may be possible over a wide range of distances from near synchronous orbit to the distant tail. It is also argued that the layer of low-energy electrons and velocity dispersed ion beams observed at low altitudes on Aureol 3 is not a different region from the region of auroral arcs. Both comprise the BPS. The two regions occasionally appear distinct at low altitudes because of the effects of arc field-aligned potential drops on precipitating particles.

  18. Asymmetric auroral intensities in the Earth's Northern and Southern hemispheres

    NASA Astrophysics Data System (ADS)

    Laundal, K. M.; Østgaard, N.

    2009-07-01

    It is commonly assumed that the aurora borealis (Northern Hemisphere) and aurora australis (Southern Hemisphere) are mirror images of each other because the charged particles causing the aurora follow the magnetic field lines connecting the two hemispheres. The particles are believed to be evenly distributed between the two hemispheres, from the source region in the equatorial plane of the magnetosphere. Although it has been shown that similar auroral features in the opposite hemispheres can be displaced tens of degree in longitude and that seasonal effects can cause differences in global intensity, the overall auroral patterns were still similar. Here we report observations that clearly contradict the common assumption about symmetric aurora: intense spots are seen at dawn in the Northern summer Hemisphere, and at dusk in the Southern winter Hemisphere. The asymmetry is interpreted in terms of inter-hemispheric currents related to seasons, which have been predicted but hitherto had not been seen.

  19. Isis 1 observations at the source of auroral kilometric radiation

    NASA Technical Reports Server (NTRS)

    Benson, R. F.; Calvert, W.

    1979-01-01

    Observations of auroral kilometric radiation (AKR) were made by Isis 1 in the source region. The radiation is found to be generated in the extraordinary mode just above the local cut-off frequency and to emanate nearly perpendicular to the magnetic field. It occurs within local depletions of electron density, where the ratio of plasma frequency to cyclotron frequency is less than 0.2. The density depletion is restricted to altitudes above about 2000 km, and the upper AKR frequency limit corresponds to the extraordinary cut-off frequency at this altitude. AKR is observed from Isis 1 above the nighttime auroral zone over a wider extent in longitude than in latitude with an intense source region observed most often near 2200 LMT and 70 deg invariant latitude. It is directly related to inverted V electron precipitation events with an electron-to-wave energy conversion efficiency of the order of 0.1 to 1%.

  20. Electric field and plasma density measurements in the auroral electrojet

    NASA Astrophysics Data System (ADS)

    Pfaff, R. F.; Kelley, M. C.; Fejer, B. G.; Kudeki, E.; Carlson, C. W.; Pedersen, A.; Hausler, B.

    1984-01-01

    Extensive experimental and theoretical studies of auroral and equatorial electrojet irregularities have been conducted for the last two decades. The present investigation is concerned with electric field and plasma density fluctuation measurements made on board of the Porcupine II sounding rocket and on a free-flyer ejected from the main spacecraft. The Porcupine II sounding rocket payload was launched at 1922:00 UT from Kiruna, Sweden, on March 20, 1977. The considered results show electrostatic turbulence in the unstable auroral E region confined to a layer between 96 and 121 km. The similarities between the observations of two simultaneous payloads spaced a few kilometers apart indicate that on a large scale, the electrojet turbulence displays uniform characteristics.

  1. On the role of magnetic mirroring in the auroral phenomena

    NASA Technical Reports Server (NTRS)

    Lennartsson, W.

    1976-01-01

    On the basis of field and particle observations, it is suggested that a bright auroral display is a part of a magnetosphere-ionosphere current system which is fed by a charge-separation process in the outer magnetosphere (or the solar wind). The upward magnetic-field-aligned current is flowing out of the display, carried mainly by downflowing electrons from the hot-particle populations in the outer magnetosphere (the ambient cold electrons being depleted at high altitudes). As a result of the magnetic mirroring of these downflowing current carriers, a large potential drop is set up along the magnetic field, increasing both the number flux and the kinetic energy of precipitating electrons. It is found that this simple basic model, when combined with wave-particle interactions, may be able to explain a highly diversified selection of auroral particle observations.

  2. Auroral electrostatic solitons and supersolitons in a magnetized nonthermal plasma

    SciTech Connect

    Rufai, O. R.

    2015-05-15

    Exploiting the spacecraft measurements in the auroral region, finite amplitude nonlinear low frequency electrostatic solitons and supersolitons in a magnetized plasma consisting of cold ions fluid, Boltzmann protons, and nonthermal hot electrons are studied by applying a pseudo-potential technique. The localized solution of the nonlinear structures is obtained through the charge neutrality condition. Further numerical investigation shows the existence of supersoliton solutions at supersonic Mach numbers regime. The amplitude of ion-acoustic structures decreased with an increase in nonthermal electrons and ion density ratio. For the plasma parameters relevant to the auroral zone of the Earth's magnetosphere, the electric field amplitude of supersolitons is found to be about 9 mV/m, which is in agreement with satellite observations.

  3. Energy flux and characteristic energy of an elemental auroral structure

    NASA Technical Reports Server (NTRS)

    Lanchester, B. S.; Palmer, J. R.; Rees, M. H.; Lummerzheim, D.; Kaila, K.; Turunen, T.

    1994-01-01

    Electron density profiles acquired with the EISCAT radar at 0.2 s time resolution, together with TV images and photometric intensities, were used to study the characteristics of thin (less than 1 km) auroral arc structures that drifted through the field of view of the instruments. It is demonstrated that both high time and space resolution are essential for deriving the input parameters of the electron flux responsible for the elemental auroral structures. One such structure required a 400 mW/sq m (erg/sq cm s) downward energy flux carried by an 8 keV monochromatic electron flux equivalent to a current density of 50 micro Angstrom/sq m.

  4. Analysis of lidar systems for profiling aurorally excited molecular species.

    PubMed

    Collins, R L; Lummerzheim, D; Smith, R W

    1997-08-20

    We report a detailed analysis of lidar systems that profile aurorally excited molecular species in the upper mesosphere and lower thermosphere ( ~80 -300 km). Current profiling of this region is performed with incoherent scatter radars that determine the total electron and ion concentrations but not the individual species. Studies of the aeronomy of the thermosphere requires knowledge of the species present and their relative populations in the different vibrational and rotational states. We review the spectroscopy of nitrogen to determine an optimized lidar system. We combine these results with current auroral observations and models to determine the performance of an actual lidar system. The study shows that such systems can provide high-resolution (1 km, 100 s) measurements of these species with current laser technology.

  5. Observations of 3-m auroral irregularities during the ERRRIS campaigns

    NASA Astrophysics Data System (ADS)

    Sahr, J. D.; Farley, D. T.; Swartz, W. E.; Providakes, J. F.; Pfaff, R. F.

    1992-06-01

    In the late winter of 1988 and 1989, three NASA sounding rockets were flown through the auroral electrojet from ESRANGE (Sweden) as part of the E-region Rocket-Radar Instability Study (ERRRIS). Many ground-based instruments supported these flights, including the EISCAT, STARE, and CUPRI radars, as well as all-sky cameras, riometers, and magnetometers. In this paper the observations of the Cornell University Portable Radar Interferometer (CUPRI), which detected coherent backscatter from 3-m irregularities in the auroral E-region are summarized. Twenty hours of power spectra and interferometry data are available, and, during the 1989 campaign, three weeks of nearly continuous Range-Time-Intensity (RTI) and first moment data were recorded.

  6. Ionospheric Convection in the Postnoon Auroral Oval: SuperDARN and Polar UVI Observations

    NASA Technical Reports Server (NTRS)

    Kozlovsky, A.; Koustov, A.; Lyatsky, W.; Kangas, J.; Parks, G.; Chua, D.

    2002-01-01

    Super Dual Auroral Radar Network (SuperDARN) observations, ultraviolet imaging from the Polar satellite (UVI), and particle precipitation data from DMSP satellites have been used to investigate the electrodynamics of the postnoon auroral oval in the Northern hemisphere. We show that: (1) For negative IMF By, the convection reversal (CR) was co-located with the maximum of auroral luminosity, but during positive IMF By the convection reversal was poleward of the auroral oval up to several degrees in latitude; (2) Postnoon auroral oval was associated with a large-scale upward field-aligned current (FAC) of the order of 6x10(exp -7). A m(exp -2) in magnitude (the FAC was inferred from the SuperDARN and UVI data). For negative IMF By, maximum of the auroral intensity coincides in latitude with the maximum of the upward field-aligned current. However, for positive IMF By. the maximum of the upward FAC was shifted to the poleward edge of the auroral oval; (3) In response to the IMF By turning from positive to negative, the maximum of the auroral luminosity did not change its position noticeably, but the position of the convection reversal changed considerably from 80-81 degs to about 76 degs MLAT, and the maximum of FAC moved from 77-78 degs to about 76 degs MLAT. Thus, after IMF By turns negative, both the FAC maximum and CR tend to coincide with the auroral maximum; (4) The IMF Bz positive deflection was followed by a decrease in both field-aligned current intensity and auroral luminosity. However, the decrease in the auroral luminosity lags behind the FAC decrease by about 12 min. Firstly, these observations allow us to suggest that the IMF By-related electric field can penetrate into the closed magnetosphere and produce convection and FAC changes in the region of the postnoon auroral oval. Secondly, we suggest that the interchange instability is a promising mechanism for the postnoon auroras.

  7. Diffuse Auroral Precipitation Caused by Wave-Particle Scattering (Invited)

    NASA Astrophysics Data System (ADS)

    Thorne, R. M.; Ni, B.; Bortnik, J.; Li, W.; Nishimura, Y.

    2013-12-01

    Diffuse auroral electron precipitation provides over 70% of ionizing energy input into the nightside upper atmosphere and is a major contribution to the global distribution of high latitude ionospheric conductivity. It is therefore important to understand the origin of the electron precipitation, since this controls the electro-dynamic coupling between the ionosphere and the magnetosphere. Intense electromagnetic whistler-mode chorus emissions and electrostatic cyclotron harmonic (ECH) waves are excited following the injection of plasma sheet electrons (100 eV - 30 keV) into the inner magnetosphere. Resonant scattering by either plasma wave can potentially cause electron precipitation into the atmosphere and subsequent diffuse auroral excitation. However, quantitative analyses of the rate of electron scattering have shown that a combination of both upper band (f > fce/2) and lower band (f < fce/2) chorus provides the dominant mechanism for nightside diffuse auroral precipitation on magnetic field lines mapping to L < 8 where the diffuse aurora is most intense, and that lower band chorus acts as the major contributor to the occurrence of the diffuse aurora on the dayside. It has also been demonstrated that pulsating aurora is cause by the modulation of lower band chorus in the wave source region deep in the magnetosphere. Since chorus emissions are now considered to be important for causing both the loss and local acceleration of high-energy (> 500 keV) radiation belt electrons, the global distribution of diffuse auroral precipitation measured either on the ground or by low altitude satellites can be used to infer the global intensity of chorus waves for subsequent radiation belt modeling.

  8. Plasma Heating and Flow in an Auroral Arc

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Chandler, M. O.; Pollock, C. J.; Reasoner, D. L.; Arnoldy, R. L.; Austin, B.; Kintner, P. M.; Bonnell, J.

    1996-01-01

    We report direct observations of the three-dimensional velocity distribution of selected topside ionospheric ion species in an auroral context between 500 and 550 km altitude. We find heating transverse to the local magnetic field in the core plasma, with significant heating of 0(+), He(+), and H(+), as well as tail heating events that occur independently of the core heating. The 0(+) velocity distribution departs from bi-Maxwellian, at one point exhibiting an apparent ring-like shape. However, these observations are shown to be aliased within the auroral arc by temporal variations that arc not well-resolved by the core plasma instrument. The dc electric field measurements reveal superthermal plasma drifts that are consistent with passage of the payload through a series of vortex structures or a larger scale circularly polarized hydromagnetic wave structure within the auroral arc. The dc electric field also shows that impulsive solitary structures, with a frequency spectrum in the ion cyclotron frequency range, occur in close correlation with the tail heating events. The drift and core heating observations lend support to the idea that core ion heating is driven at low altitudes by rapid convective motions imposed by the magnetosphere. Plasma wave emissions at ion frequencies and parallel heating of the low-energy electron plasma are observed in conjunction with this auroral form; however, the conditions are much more complex than those typically invoked in previous theoretical treatments of superthermal frictional heating. The observed ion heating within the arc clearly exceeds that expected from frictional heating for the light ion species H(+) and He(+), and the core distributions also contain hot transverse tails, indicating an anomalous transverse heat source.

  9. Chatanika Radar Measurements during the Auroral E Program

    DTIC Science & Technology

    1981-06-01

    region neutral winds have biased the elevation scan measurements. 16 0 WIAW -- 3 * I I I 0 -r I co I Iz aa ’I 0 Ii z J-4 * I i I0 0 w -J w4j w Cc 0 ~I U...V. Starkov , "Dynamics of Auroral Belt and Polar Geomagnetic Disturbances," Planet. Sp. Sci., 15, 209-229 (1967). Gussenhoven, M. S., D. A. Hardy

  10. Russian auroral and polar ionospheric disturbance magnetometers (RapidMag)

    NASA Astrophysics Data System (ADS)

    Takahashi, K.; Meng, C. I.; Barnes, R. J.; Zetzer, J.; Troshichev, O.; Janzhura, A.; Kunitake, M.; Watari, S.; Iyemori, T.; Nosé, M.; Keiling, A.; Angelopoulos, V.

    2007-12-01

    Since their introduction by Davis and Sugiura in 1966, the auroral electrojet indices AE, AU, and AL have been widely used to study ionospheric and magnetospheric phenomena associated with substorms as well as input to magnetospheric and ionospheric models. While rapid delivery of the indices is highly desirable in the context of both ongoing scientific observations and space weather applications, production of near-real-time AE indices remains a difficult task. A major challenge is acquisition of near-real-time magnetometer data from Russian auroral zone stations, some of which are at remote locations with harsh natural environment and without well- established infrastructure for data transmission. The stations cover approximately 6 time zones, and missing data from the stations means a serious degradation of the AE indices. The Russian auroral and polar ionospheric disturbance Magnetometer (RapidMag) project is an international collaboration to enable rapid and stable acquisition of ground magnetometer data from Russian stations in the auroral zone for production of near- real-time AE indices as well as for distribution of data from individual stations to the science community. The six RapidMag stations are Amderma (65.1N, 138.1E, degrees, geomagnetic), Dikson Island (68.5N, 156.2E), Norilsk (64.6N, 161.9E), Cape Chelyuskin (71.8N, 175.6E), Tixie (65.9°N, 196.9°E), and Pebek (65.3°N, 228.8E). The RapidMag project is entering a new phase with recent funding from NSF and NASA. We present the current status of the project and our plan for the next 5 years.

  11. Natural and artificially injected electron fluxes near discrete auroral arcs

    NASA Technical Reports Server (NTRS)

    Wilhelm, K.

    1980-01-01

    A sounding rocket payload instrumented in order to inject and observe energetic electron fluxes in the ionospheric plasma was flown from Ft. Churchill into a bright auroral display on 9 April 1978. Measurements of one throw-away detector in three energy channels at 1.9, 4 and 8 keV are discussed in order to relate the observed electron echoes to the prevailing geophysical conditions.

  12. Particle simulation of auroral double layers. Doctoral thesis

    SciTech Connect

    Smith, B.L.

    1992-06-01

    Externally driven magnetic reconnection has been proposed as a possible mechanism for production of auroral electrons during magnetic substorms. Fluid simulations of magnetic reconnection lead to strong plasma flows towards the increasing magnetic field of the earth. These plasma flows must generate large scale potential drops to preserve global charge neutrality. We have examined currentless injection of plasma along a dipole magnetic field into a bounded region using both analytic techniques and particle simulation.

  13. Saturation and energy-conversion efficiency of auroral kilometric radiation

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Tsai, S. T.; Xu, M. J.; Shen, J. W.

    1981-01-01

    A quasi-linear theory is used to study the saturation level of the auroral kilometric radiation. The investigation is based on the assumption that the emission is due to a cyclotron maser instability as suggested by Wu and Lee and Lee et al. The thermodynamic bound on the radiation energy is also estimated separately. The energy-conversion efficiency of the radiation process is discussed. The results are consistent with observations.

  14. Ionization from soft electron precipitation in the auroral F region

    NASA Technical Reports Server (NTRS)

    Labelle, J.; Sica, R. J.; Kletzing, C.; Earle, G. D.; Kelley, M. C.

    1989-01-01

    Rocket-borne instrumentation, launched into the morning sector auroral zone from Sondre Stromfjord, Greenland, detects electron density enhancements correlated with enhancements in the flux of soft (less than 1 keV) downgoing electrons. These electron density enhancements seem most likely to have been generated by direct production of ionization at F region altitudes. Model calculations of the electron impact ionization rate, based on the measured electron spectrum, lend support to this hypothesis.

  15. 3D modelling of stellar auroral radio emission

    NASA Astrophysics Data System (ADS)

    Leto, P.; Trigilio, C.; Buemi, C. S.; Umana, G.; Ingallinera, A.; Cerrigone, L.

    2016-06-01

    The electron cyclotron maser is the coherent emission process that gives rise to the radio lighthouse effect observed in the hot magnetic chemically peculiar star CU Virginis. It has also been proposed to explain the highly circularly polarized radio pulses observed in some ultracool dwarfs with spectral type earlier than M7. Coherent events of this kind resemble auroral radio emission from the magnetized planets of the Solar system. In this article, we present a three-dimensional model able to simulate the timing and profile of the pulses emitted by those stars characterized by a dipolar magnetic field by following the hypothesis of the laminar source model, used to explain the beaming of terrestrial auroral kilometric radiation. This model proves to be a powerful tool with which to understand the auroral radio emission phenomenon, allowing us to derive some general conclusions about the effects of the model's free parameters on the features of coherent pulses and to learn more about the detectability of such pulsed radio emission.

  16. Auroral Workshop generates U.S.-Finnish teamwork

    NASA Astrophysics Data System (ADS)

    Moldwin, Mark

    Forty scientists from the United States and Finland met last spring at a workshop to develop collaborative studies of magnetospheric-ionospheric coupling and to synthesize multiple ground-based and space-based data sets. The workshop also provided an opportunity to compare the output of new U.S. and Finnish Global Magnetohydrodynamic models with ground-based and satellite observations. Some of the missions and facilities that are providing new data within the United States and Finland include the Global Geospace Science/national Solar-Terrestrial Program Polar and Wind satellites, Interball, the Fast Auroral Snapshot Explorer, the Solar and Heliospheric Observatory, Ulysses, the Svalbard Radar, the new Super Dual Auroral Radar Network (SuperDARN) station, digital all sky cameras, and the Magnetosphere Imager (MI) array in Finland. The workshop began with a discussion of dayside magnetospheric-ionospheric coupling. Dayside ionospheric transient signatures were divided into three types: auroral forms and convection velocity spikes, magnetic and convection events, and twin convection vortices. The three classes differ in size, location, repetition rates, and Interplanetary Magnetic Field (IMF) dependencies. Scientists are addressing whether the transient classes are related, what the transients' role is compared to that of permanent cusp features, and how transients affect mag-netospheric energetics.

  17. The Auroral Planetary Imaging and Spectroscopy (APIS) service

    NASA Astrophysics Data System (ADS)

    Lamy, L.; Prangé, R.; Henry, F.; Le Sidaner, P.

    2015-06-01

    The Auroral Planetary Imaging and Spectroscopy (APIS) service, accessible online, provides an open and interactive access to processed auroral observations of the outer planets and their satellites. Such observations are of interest for a wide community at the interface between planetology, magnetospheric and heliospheric physics. APIS consists of (i) a high level database, built from planetary auroral observations acquired by the Hubble Space Telescope (HST) since 1997 with its mostly used Far-Ultraviolet spectro-imagers, (ii) a dedicated search interface aimed at browsing efficiently this database through relevant conditional search criteria and (iii) the ability to interactively work with the data online through plotting tools developed by the Virtual Observatory (VO) community, such as Aladin and Specview. This service is VO compliant and can therefore also been queried by external search tools of the VO community. The diversity of available data and the capability to sort them out by relevant physical criteria shall in particular facilitate statistical studies, on long-term scales and/or multi-instrumental multi-spectral combined analysis.

  18. Observations of transverse ion acceleration in the topside auroral ionosphere

    NASA Technical Reports Server (NTRS)

    Garbe, G. P.; Arnoldy, R. L.; Moore, T. E.; Kintner, P. M.; Vago, J. L.

    1992-01-01

    The paper reports data obtained from a sounding rocket flight which reached an apogee of 927 km and passed through several auroral arcs. Therma/superthermal ions were sampled by charged particle analyzers which allowed for a rapid (about 1 s) sampling of their distribution function. During portions of the flight when the rocket was not in an energetic auroral structure, the ion data are fit to a Maxwellian function which yields the plasma parameters. Throughout the middle portion of the flight, above 700-km altitude, ion distributions having a superthermal tail were measured. When the rocket was immersed in energetic auroral electron precipitation, two other ion distributions were observed. Transversely accelerated ions which represented bulk heating of the ambient population were observed continuously in these arcs. The characteristic perpendicular energy of the transversely bulk heated ions reached as high as 3 eV compared to typically less than 0.4 eV during nonauroral times. The observations are discussed in terms of some current theories of transverse ion energization.

  19. Instrument for the monochromatic observation of all sky auroral images.

    PubMed

    Mende, S B; Eather, R H; Aamodt, E K

    1977-06-01

    To investigate the dynamics of auroras and faint upper atmospheric emissions, a new type of imaging instrument was developed. The instrument is a wide field of view, narrow-spectral-band imaging system using an intensified S.E.C. TV camera in a time exposure mode. Pictures were taken at very low light levels of a few photons per exposure per resolution element. These pictures are displayed in the form of a pseudocolor presentation in which the color represents spectral ratios of two of the observed auroral spectral emission features. The spectral ratios play an important part in the interpretation of auroral particle dynamics. A digital picture processing facility is also part of the system which enables the digital manppulation of the pictures at standard TV rates. As an example, hydrogen auroras can be displayed having been corrected for nonspectral background by subtracting a picture obtained by a suitable background filter. The instrumentation was calibrated in the laboratory and was used in several field xperiments. Elaborate exposure sequences were developed to extend the dynamic range and to cover the large range of auroral brightnesses in a fairly linear manner.

  20. Observations of joule and particle heating in the auroral zone

    NASA Technical Reports Server (NTRS)

    Banks, P. M.

    1977-01-01

    Observational data from the Chatanika, Alaska incoherent scatter radar have been used to deduce atmospheric heating rates associated with particle precipitation and joule dissipation. During periods when Chatanika is in the vicinity of the auroral oval the height-integrated heat input to the lower thermosphere can be as large as 100 ergs per sq cm per sec with joule and particle heating rates of comparable magnitude. Altitude profiles of these heat inputs are also obtained, showing that the energy liberated by joule dissipation tends to peak at a substantially higher altitude (about 130 km) than that due to particles (100-120 km). As a consequence, it follows that joule heating can be expected to provide a rapid means for creating thermospheric disturbances. It is also pointed out that joule and particle heating are permanent features of the auroral oval and polar cap. As such, expansion of the auroral oval leads to an increase in the total global heating and, hence, to the close relationship between magnetic disturbances and thermospheric perturbation.

  1. Observing the magnetosphere through global auroral imaging: 2. Observing techniques

    NASA Astrophysics Data System (ADS)

    Mende, Stephen B.

    2016-10-01

    In a companion paper four auroral regions were identified. The source of the first three regions is the plasma sheet, whereas the source of the fourth, the region of Alfvenic auroras, is the ionosphere. It is a primary goal of global auroral imaging to identify these source regions. Space-based imaging can be used to obtain ion and electron, mean energy, and energy flux as a basis for such identification. Measurement of direct emission from precipitating ions or their charge exchange products can be used to determine the ion precipitation characteristics. For electrons, it is necessary to use the atmosphere as a spectrometer. Total precipitated energy can be derived from the luminosity of spectral features where the production cross sections are known. The mean energy of precipitation is inferred from the luminosity height profile deduced from (1) collisional quenching of long lifetime emitters, (2) atmospheric composition, (3) degree of O2 absorption in the UV, or (4) the local atmospheric neutral temperature. There are fundamental advantages in viewing the aurora from space; for example, auroras can be observed in the far ultraviolet range where daylight contamination is much less severe. The various approaches to spaceborne auroral imaging depend on the wavelength selection requirements. UV interferometers show promise of improved light collection efficiency and higher spectral resolution.

  2. Features of the processes of ion heating in polar boundary of the night auroral oval

    NASA Astrophysics Data System (ADS)

    Chugunin, Dmitriy; Lutsenko, Volt; Romantsova, Tatiana; Mogilevsky, Mikhail; Moiseenko, Irina

    Investigation of the processes of ion heating in polar boundary of the night auroral oval measured by INTERBALL-2 (Auroral probe) is presented. Measurements of particles and waves were made on altitude about 20000 км. Feature of the orbits was the satellite slid along auroral oval and stay long time in the auroral zone. It were cases chosen when the polar boundary moved and passed through satellite. Particular attention is given to ions heating at this border and to ion heating position in relation to polar boundary of particle precipitation.

  3. Summary of Chernobyl followup research activities

    SciTech Connect

    Not Available

    1992-06-01

    In NUREG-1251, ``Implications of the Accident at Chernobyl for Safety Regulation of Commercial Nuclear Power Plants in the United States,`` April 1989, the NRC staff concluded that no immediate changes in NRC`s regulations regarding design or operation of US commercial reactors were needed; however, it recommended that certain issues be considered further. NRC`s Chernobyl followup research program consisted of the research tasks undertaken in response to the recommendations in NUREG-1251. It included 23 tasks that addressed potential lessons to be learned from the Chernobyl accident. This report presents summaries of NRC`s Chernobyl followup research tasks. For each task, the Chernobyl-related issues are indicated, the work is described, and the staff`s findings and conclusions are presented. More detailed reports concerning the work are referenced where applicable. This report closes out NRC`s Chernobyl followup research program as such, but additional research will be conducted on some issues as needed. The report includes remarks concerning significant further activity with respect to the issues addressed.

  4. Summary of Chernobyl followup research activities

    SciTech Connect

    Not Available

    1992-06-01

    In NUREG-1251, Implications of the Accident at Chernobyl for Safety Regulation of Commercial Nuclear Power Plants in the United States,'' April 1989, the NRC staff concluded that no immediate changes in NRC's regulations regarding design or operation of US commercial reactors were needed; however, it recommended that certain issues be considered further. NRC's Chernobyl followup research program consisted of the research tasks undertaken in response to the recommendations in NUREG-1251. It included 23 tasks that addressed potential lessons to be learned from the Chernobyl accident. This report presents summaries of NRC's Chernobyl followup research tasks. For each task, the Chernobyl-related issues are indicated, the work is described, and the staff's findings and conclusions are presented. More detailed reports concerning the work are referenced where applicable. This report closes out NRC's Chernobyl followup research program as such, but additional research will be conducted on some issues as needed. The report includes remarks concerning significant further activity with respect to the issues addressed.

  5. VASIMR Simulation Studies of Auroral Ion Cyclotron Heating

    NASA Astrophysics Data System (ADS)

    Brukardt, M.; Bering, E. A.; Chang-Diaz, F. R.; Squire, J. P.; Glover, T. W.; Jacobs0n, V. T.; McCaskill, G. E.; Cassady, L. D.; Bengtson, R. D.

    2006-12-01

    Plasma physics has found an increasing range of practical industrial applications, including the development of electric spacecraft propulsion systems. One of these systems, the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) engine, both applies and can be used to simulate several important physical processes occurring in the magnetosphere. These processes include the mechanisms involved in the ion acceleration and heating that occur in the Birkeland currents of an auroral arc system. Auroral current region processes that are simulated in VASIMR include lower hybrid heating, parallel electric field acceleration and ion cyclotron acceleration. This paper will focus on using a physics demonstration model VASIMR to study ion cyclotron heating (ICRH) similar to auroral zone processes. The production of upward moving `ion conics' and ion heating are significant features in auroral processes. It is believed that ion cyclotron heating plays a role in these processes, but laboratory simulation of these auroral effects is difficult owing to the fact that the ions involved only pass through the acceleration region once. In the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) we have successfully simulated these effects. The current configuration of the VASIMR uses a helicon antenna with up to 20 kW of power to generate plasma then uses an RF booster stage that uses left hand polarized slow mode waves launched from the high field side of the resonance. The current setup for the booster uses 2 to 4 MHz waves with up to 20 kW of power. This is similar to the ion cyclotron heating in tokamaks, but in the VASIMR the ions only pass through the resonance region once. The rapid absorption of ion cyclotron waves has been predicted in recent theoretical studies. These theoretical predictions have been confirmed with several independent measurements. The ion cyclotron resonance heating (ICRH) shows a substantial increase in ion velocity. Pitch angle distribution studies

  6. Morphology of Southern Hemisphere Riometer Auroral Absorption

    DTIC Science & Technology

    2006-06-01

    Research, Japan, which funded my research stay there. Support for this study has also come from the Chilean Fondo Nacional de Desarrollo Científico y...Administration Technical Report IER-1-ITSA 1, U.S. Government Printing Office. [7] Bilitza, D. (1992) “Solar-terrestrial model and application software

  7. IFM-Modeled Response of the High-Latitude Ionosphere to Auroral Dynamics Based on Auroral Observations Acquired with the Visible Imaging System(VIS) on the Polar Spacecraft

    NASA Astrophysics Data System (ADS)

    Bekerat, H.; Sigwarth, J.; Schunk, R.; Eccles, V.

    2007-12-01

    Global physics-based models for the high-latitude ionosphere have been developed to such an extent that the large and small ionospheric features during magnetic storms and substorms can be studied. These models, however, require inputs for the magnetospheric forcing, i.e. Magnetospheric convection and particle precipitation. More specifically, for these models to yield reliable results during magnetic storms and substorms, reliable global maps for the high-latitude magnetospheric convection and auroral electron particle precipitation patterns as a function of time are needed. Over the last decades several statistical models for the high-latitude convection and particle precipitation have been developed and used to drive ionospheric models. However, due to the statistical nature of these models, they represent the average characteristics of the true convection and precipitation patten and they are very limited to simulate the effect of magnetic storms and substorms. Recently, with the realization of the Visible Imaging System (VIS) on the Polar Spacecraft, auroral images that yield information of auroral dynamics on a global scale with a spatial resolution of less than 100 km and temporal resolution of ~ 1 minute have become available. These images can be used to calculate reliable global maps for the particle precipitation parameters, electron energy flux and average energies, as a function of time. In this poster we present the preliminary results of our attempt to drive the Ionosphere Forecast Model (IFM) using global maps for the electron precipitation parameters calculated from the corresponding VIS images. In order to elucidate the effect of auroral dynamics on the high-latitude ionosphere, a one-day data set of VIS images during which the aurora was highly active is selected for this study. Then, these images are used to calculate global maps for the electron precipitation parameters using the Lumerzheim model. Next, the maps obtained in the previous step are

  8. Substorm auroral onset triggering by flow-wave interaction detected with high-resolution radar and imager measurements

    NASA Astrophysics Data System (ADS)

    Nishimura, T.; Lyons, L. R.; Zou, Y.; Bristow, W. A.; Hampton, D. L.; Nicolls, M. J.; Michell, R.; Samara, M.; Angelopoulos, V.; Donovan, E.; Spanswick, E.

    2013-12-01

    A critical, long-standing problem in substorm research is identification of the sequence of events leading to substorm auroral onset. THEMIS all-sky imager (ASI) array observations have revealed a repeatable pre-onset sequence that begins with a poleward boundary intensification (PBI) followed by a north-south oriented streamer moving equatorward. Substorm auroral onset occurs soon after the streamer reaches near the substorm onset location. Since fast magnetotail flows are linked to PBIs and streamers, this sequence indicates that onset is preceded by enhanced earthward plasma flows associated with a localized reconnection region near the pre-existing open-closed field line boundary. On the other hand, THEMIS satellite and ASIs also show that substorms are preceded by azimuthally propagating waves of ~1-2 min periodicity, indicating that a wave mode within the near-Earth plasma sheet is important for triggering substorm onset. However, it has been difficult to identify the link between fast earthward flows and these near-Earth waves. We have found a substorm event for which there is excellent coverage from the Poker Flat incoherent scatter radar (PFISR), THEMIS white light and multi-spectral ASIs, where the auroral onset occurred within the PFISR field of view near the zenith of the ASIs. The substorm onset was preceded by a PBI, and one of the radar beams going through the PBI detected equatorward flows and reaching the growth phase arc. The flows appear to propagate from open magnetic field lines across the open-closed boundary, leading to the PBI and then to onset soon after they reach the near-Earth plasma sheet. We also identified oscillations of auroral luminosity along the growth phase arc with a ~1 min period. These waves were propagating westward with only small intensity variations. Soon after the equatorward flows reached the growth phase arc, the wave luminosity amplified abruptly, denoting the onset of a substorm. Based on this sequence, we suggest

  9. The northern light. From mythology to space research.

    NASA Astrophysics Data System (ADS)

    Brekke, A.; Egeland, A.

    Contents: The northern light in folklore and mythology. The northern light in Norse literature. The northern light - a source of inspiration. Accounts of northern lights in Scandinavia - from the Viking era to the Renaissance. The northern light in Scandinavia during the eighteenth century. Scientific auroral experiments beginning in the nineteenth century. Norwegian auroral pioneers in the dawn of our century. The northern lights as weather signs - and the auroral sound. Northern lights and geomagnetic disturbances - their influence on daily life. Auroral research as a tool to study the upper atmosphere and near space. The first systematic observations of the northern light in Norway. Summary and concluding remarks.

  10. Frontier Geoplasma Research Ionosphere, Polar, Auroral, Coupling Processes

    DTIC Science & Technology

    2007-11-02

    of New Hampshire, Dartmouth College, Boston College, the Max-Planck Institutes for Extraterrestrial Physics and of Aeronomy, the Utah State...cavitary structures all have profound effects on the high- latitude electron and ion density profiles as well as signal and wave propagations. The...Union on Radio Science, Lille, France, August 1996. "* Chapman Conference on the Magnetotail: New Perspectives, Kanazawa, Japan, November 1996

  11. An overview of Japanese CELSS research activities

    NASA Technical Reports Server (NTRS)

    Nitta, Keiji

    1987-01-01

    Development of Controlled Ecological Life Support System (CELSS) technology is inevitable for future long duration stays of human beings in space, for lunar base construction and for manned Mars flight programs. CELSS functions can be divided into 2 categories, Environmental Control and Material Recycling. Temperature, humidity, total atmospheric pressure and partial pressure of oxygen and carbon dioxide, necessary for all living things, are to be controlled by the environment control function. This function can be performed by technologies already developed and used as the Environment Control Life Support System (ECLSS) of Space Shuttle and Space Station. As for material recycling, matured technologies have not yet been established for fully satisfying the specific metabolic requirements of each living thing including human beings. Therefore, research activities for establishing CELSS technology should be focused on material recycling technologies using biological systems such as plants and animals and physico-chemical systems, for example, a gas recycling system, a water purifying and recycling system and a waste management system. Japanese research activities were conducted and will be continued accordingly.

  12. Positive Activities: Qualitative Research with Parents. Solutions Research. Research Report. DCSF-RR142

    ERIC Educational Resources Information Center

    Department for Children, Schools and Families, 2009

    2009-01-01

    This research was commissioned by COI and DCSF to understand in depth, the barriers, motivators and messages for parents to encourage participation in positive activities for young people. Within this the research was designed to understand the level of influence of parents in whether a young person participates/what a young person might…

  13. Electromechanically active polymer transducers: research in Europe

    NASA Astrophysics Data System (ADS)

    Carpi, Federico; Graz, Ingrid; Jager, Edwin; Ladegaard Skov, Anne; Vidal, Frédéric

    2013-10-01

    Smart materials and structures based on electromechanically active polymers (EAPs) represent a fast growing and stimulating field of research and development. EAPs are materials capable of changing dimensions and/or shape in response to suitable electrical stimuli. They are commonly classified in two major families: ionic EAPs (activated by an electrically induced transport of ions and/or solvent) and electronic EAPs (activated by electrostatic forces). These polymers show interesting properties, such as sizable active strains and/or stresses in response to electrical driving, high mechanical flexibility, low density, structural simplicity, ease of processing and scalability, no acoustic noise and, in most cases, low costs. Since many of these characteristics can also describe natural muscle tissues from an engineering standpoint, it is not surprising that EAP transducers are sometimes also referred to as 'muscle-like smart materials' or 'artificial muscles'. They are used not only to generate motion, but also to sense or harvest energy from it. In particular, EAP electromechanical transducers are studied for applications that can benefit from their 'biomimetic' characteristics, with possible usages from the micro- to the macro-scale, spanning several disciplines, such as mechatronics, robotics, automation, biotechnology and biomedical engineering, haptics, fluidics, optics and acoustics. Currently, the EAP field is just undergoing its initial transition from academic research into commercialization, with companies starting to invest in this technology and the first products appearing on the market. This focus issue is intentionally aimed at gathering contributions from the most influential European groups working in the EAP field. In fact, today Europe hosts the broadest EAP community worldwide. The rapid expansion of the EAP field in Europe, where it historically has strong roots, has stimulated the creation of the 'European Scientific Network for Artificial

  14. FAST/Polar Conjunction Study of Field-Aligned Auroral Acceleration and Corresponding Magnetotail Drivers

    NASA Technical Reports Server (NTRS)

    Schriver, D.; Ashour-Abdalla, M.; Strangeway, R. J.; Richard, R. L.; Klezting, C.; Dotan, Y.; Wygant, J.

    2002-01-01

    The discrete aurora results when energized electrons bombard the Earth's atmosphere at high latitudes. This paper examines the physical processes that can cause field-aligned acceleration of plasma particles in the auroral region. A data and theoretical study has been carried out to examine the acceleration mechanisms that operate in the auroral zone and to identity the magnetospheric drivers of these acceleration mechanisms. The observations used in the study were collected by the Fast Auroral SnapshoT (FAST) and Polar satellites when the two satellites were in approximate magnetic conjunction in the auroral region. During these events FAST was in the middle of the auroral zone and Polar was above the auroral zone in the near-Earth plasma sheet. Polar data was used to determine the conditions in the magnetotail at the time field-aligned acceleration was measured by FAST in the auroral zone. For each of the magnetotail drivers identified in the data study, the physics of field-aligned acceleration in the auroral region was examined using existing theoretical efforts and a long-system particle-in-cell simulation to model the magnetically connected region between the two satellites.

  15. Measurement of the cross spectrum of HF electrostatic waves in an auroral plasma

    NASA Astrophysics Data System (ADS)

    Pottelette, R.; Illiano, J. M.

    1983-06-01

    A method for the metrology of space plasmas, based on the reception of electrostatic waves by a pair of small dipole antennas was tested in PORCUPINE project rocket experiments. Both dipoles received signals from the natural electrostatic microfield in the plasma; the cross spectrum of these random signals was measured. Data obtained during a weak auroral activity are presented. Natural electrostatic emissions were observed around the upper hybrid frequency and also around the three-halves harmonic of the electron gyrofrequency. A linear calculation shows that the amplitudes of these emissions are above the thermal noise level of the plasma. To explain the observations, it is necessary to take into account the presence of low-energy precipitating electrons (1 to 20 eV), which are highly anisotropic.

  16. Energy parameters of precipitating auroral electrons obtained by using photometric observations

    SciTech Connect

    Ono, Takayuki; Morishima, Kei )

    1994-02-15

    The authors present a ground based photometric method for measuring both the average energy and total energy flux for active discrete auroras. They make use of a multichannel photometer, with a narrow field of view. They monitor auroral emissions from atomic states and molecular bands, and by determining intensity ratios, are able to infer information relative to energy parameters of precipitating electrons in discrete arcs. They are able to look along magnetic axes. One observation is that there is a relationship between the energy flux and average energy, which can be considered ohmic in character, consistent with a model that precipitating electrons are accelerated along field lines by potential differences which can exist along these field lines.

  17. Relations between the Birkeland currents, the auroral electrojet indices and high latitude Joule heating

    NASA Technical Reports Server (NTRS)

    Nisbet, J. S.

    1982-01-01

    Field-aligned currents were postulated by Birkeland (1908) to explain the magnetic perturbations in the auroral zone. Theoretical models have been developed to examine the effect of these currents on the ionosphere. These models, in general, involve very extensive computer programs, and it is difficult to see how their very complicated boundary conditions and assumptions affect the relationships between the Birkeland currents and magnetic activity. In the present investigation, a simplified analysis is used to study the average behavior of the large-scale ionospheric current paths and to examine the interrelationships of various parameters. The relationship of the parameters of the current deposition regions to the magnetic indices is investigated along with the polar cap potential. Attention is given to the experimental values of coefficients, and relations between the Birkeland current densities, current intensities, currents, and the AL, AU, AE indices are discussed.

  18. Dynamic auroral storms on Saturn as observed by the Hubble Space Telescope.

    PubMed

    Nichols, J D; Badman, S V; Baines, K H; Brown, R H; Bunce, E J; Clarke, J T; Cowley, S W H; Crary, F J; Dougherty, M K; Gérard, J-C; Grocott, A; Grodent, D; Kurth, W S; Melin, H; Mitchell, D G; Pryor, W R; Stallard, T S

    2014-05-28

    We present observations of significant dynamics within two UV auroral storms observed on Saturn using the Hubble Space Telescope in April/May 2013. Specifically, we discuss bursts of auroral emission observed at the poleward boundary of a solar wind-induced auroral storm, propagating at ∼330% rigid corotation from near ∼01 h LT toward ∼08 h LT. We suggest that these are indicative of ongoing, bursty reconnection of lobe flux in the magnetotail, providing strong evidence that Saturn's auroral storms are caused by large-scale flux closure. We also discuss the later evolution of a similar storm and show that the emission maps to the trailing region of an energetic neutral atom enhancement. We thus identify the auroral form with the upward field-aligned continuity currents flowing into the associated partial ring current.

  19. Dynamic auroral storms on Saturn as observed by the Hubble Space Telescope

    PubMed Central

    Nichols, J D; Badman, S V; Baines, K H; Brown, R H; Bunce, E J; Clarke, J T; Cowley, S W H; Crary, F J; Dougherty, M K; Gérard, J-C; Grocott, A; Grodent, D; Kurth, W S; Melin, H; Mitchell, D G; Pryor, W R; Stallard, T S

    2014-01-01

    We present observations of significant dynamics within two UV auroral storms observed on Saturn using the Hubble Space Telescope in April/May 2013. Specifically, we discuss bursts of auroral emission observed at the poleward boundary of a solar wind-induced auroral storm, propagating at ∼330% rigid corotation from near ∼01 h LT toward ∼08 h LT. We suggest that these are indicative of ongoing, bursty reconnection of lobe flux in the magnetotail, providing strong evidence that Saturn's auroral storms are caused by large-scale flux closure. We also discuss the later evolution of a similar storm and show that the emission maps to the trailing region of an energetic neutral atom enhancement. We thus identify the auroral form with the upward field-aligned continuity currents flowing into the associated partial ring current. PMID:26074636

  20. The auroral ionosphere TEC response to an interplanetary shock

    NASA Astrophysics Data System (ADS)

    Jin, Yaqi; Zhou, Xiaoyan; Moen, Jøran I.; Hairston, Marc

    2016-03-01

    This letter investigates the global total electron content (TEC) response in the auroral ionosphere to an interplanetary shock on 8 March 2012, using GPS TEC data from three pierce point chains. One is a longitudinal chain along ~65° magnetic latitude (MLAT) from ~19 magnetic local time (MLT) through dayside to 03 MLT clockwise; one meridional chain is around 14 MLT from 88° to 59° MLAT; and the third one is a chain along ~75° MLAT from ~14 to 00 MLT clockwise. The first chain clearly presents a TEC signal propagation away from ~14 MLT, indicating the shock impact location. Such a propagation is well consistent with the diffuse shock aurora propagation, and the impact location is well predicted by the shock normal direction calculated using the Geotail solar wind and interplanetary magnetic field data. The meridional chain reveals a very fast TEC signal equatorward expansion at ~45 km/s, which is the manifestation of the shock impact and further compression near the subsolar magnetopause. While TEC along the high-latitude chain varies randomly, lacking any pattern, it is consistent with the discrete aurora dynamics along the poleward boundary of the auroral oval. These findings strongly support the shock aurora mechanisms of adiabatic compression and field-aligned current establishment or enhancement, suggest that due to the same mechanisms a shock-generated TEC variation is a "duplication" of the shock aurora from the global picture to the auroral forms and their dynamics, and open the door for the TEC to be an important tool to understand the solar wind and geospace coupling. These results, for the first time, reveal the prompt, intense, and global ionospheric TEC response to the interplanetary fast-forward shock.

  1. Cluster Multi-Point Studies of the Auroral Acceleration Region

    NASA Astrophysics Data System (ADS)

    Marklund, G. T.

    2014-12-01

    Multi-point studies of the auroral acceleration region (AAR) by the Cluster spacecraft has enabled a number of open issues on the auroral acceleration to be addressed and revealed. Data from AAR crossings of Inverted-V aurora, by the C1 and C3 spacecraft at different altitudes, enabled a detailed reconstruction of the acceleration potential and a verification of its stability on a five min time scale. The relative role of quasi-static and Alfvénic acceleration behind aurora are addressed in two event studies. In one of these, the two processes are shown to operate jointly on the plasma population within the polar cap boundary. In the other, the electron energy flux producing multiple arcs within a surge is found to be generally dominated by the quasi-static contribution. Acceleration features and the FAC closure associated with surge-horn aurora crossed by the Cluster fleet were derived in another event study. A study of the density distribution within the auroral cavity, showed for all included events, exponential density decreases, relative to the ambient densities, from the mid to top of the AAR. In another study, cavities were found to extend well beyond the top of the AAR. Finally, statistical high-latitude electric field and plasma density distributions are presented based on 10 years of Cluster data collected between 2 and 4 RE altitudes. Intense electric fields appear in two altitude regimes on the nightside, separated by a gap at 2.8 RE. The upper altitude fields were interpreted to be Alfvénic and the lower altitude fields quasi-static, related to the AAR. The gap in the electric field intensity indicates a partial closure of the potentials in the lower region, with similarities to model results of reflected Alfvén waves and earlier reported observations

  2. Auroral arc and oval electrodynamics in the Harang region

    NASA Astrophysics Data System (ADS)

    Marghitu, O.; Karlsson, T.; Klecker, B.; Haerendel, G.; McFadden, J.

    2009-03-01

    Auroral arcs are typically described in terms of an upward field-aligned current (FAC) sheet above the arc, connected by ionospheric Pedersen current to a downward FAC sheet near the arc. On the basis of data measured by the FAST spacecraft, conjugate with ground optical observations, we present first a wide and stable winter evening arc, where this standard model does not apply. The arc is observed in the Harang region during the growth phase of a modest substorm, poleward of the convection reversal (CR) boundary. Although the magnetic field data suggest the typical configuration, the two FAC sheets appear to be decoupled near the satellite footprint: the upward FAC is fed by the westward electrojet (WEJ), while the downward FAC feeds the eastward electrojet (EEJ). The examination of the arc by the newly developed ALADYN technique confirms this peculiar current topology. For comparison, we apply ALADYN also to a second evening arc, located within the Harang region equatorward from the CR. The arc is confirmed to have the standard configuration, consistent with a former study, but substantial FAC-EJ coupling is inferred in the auroral oval both poleward and equatorward of the arc. A key element for the topology of the current closure is the westward component of the electric field, which influences the relative location of the CR with respect to the large-scale FAC reversal (FR) boundary. As proved by tests on synthetic data, a westward component of the electric field pushes the CR toward the FR, preventing thus the standard FAC closure, while the conductance and FAC pattern shape the CR profile. Since a westward electric field is often measured in the Harang region, the FAC-EJ coupling is expected to be an essential ingredient there. This has important implications for the current closure in the equatorial magnetosphere and for the auroral current circuit in the WEJ region, closely related to the substorm process.

  3. A Statistical Analysis of Langmuir Wave-Electron Correlations Observed by the CHARM II Auroral Sounding Rocket

    NASA Astrophysics Data System (ADS)

    Dombrowski, M. P.; Labelle, J. W.; Kletzing, C.; Bounds, S. R.; Kaeppler, S. R.

    2014-12-01

    Langmuir-mode electron plasma waves are frequently observed by spacecraft in active plasma environments such as the ionosphere. Ionospheric Langmuir waves may be excited by the bump-on-tail instability generated by impinging beams of electrons traveling parallel to the background magnetic field (B). The Correlation of High-frequencies and Auroral Roar Measurement (CHARM II) sounding rocket was launched into a substorm at 9:49 UT on 17 February 2010, from the Poker Flat Research Range in Alaska. The primary instruments included the University of Iowa Wave-Particle Correlator (WPC), the Dartmouth High-Frequency Experiment (HFE), several charged particle detectors, low-frequency wave instruments, and a magnetometer. The HFE is a receiver system which effectively yields continuous (100% duty cycle) electric-field waveform measurements from 100 kHz to 5 MHz, and which had its detection axis aligned nominally parallel to B. The HFE output was fed on-payload to the WPC, which uses a phase-locked loop to track the incoming wave frequency with the most power, then sorting incoming electrons at eight energy levels into sixteen wave-phase bins. CHARM II encountered several regions of strong Langmuir wave activity throughout its 15-minute flight, and the WPC showed wave-lock and statistically significant particle correlation distributions during several time periods. We show results of an in-depth analysis of the CHARM II WPC data for the entire flight, including statistical analysis of correlations which show evidence of direct interaction with the Langmuir waves, indicating (at various times) trapping of particles and both driving and damping of Langmuir waves by particles. In particular, the sign of the gradient in particle flux appears to correlate with the phase relation between the electrons and the wave field, with possible implications for the wave physics.

  4. Auroral X-ray detection from rocket overflights

    NASA Technical Reports Server (NTRS)

    Goldberg, A.; Barcus, J. R.; Gesell, L. H.; Vondrak, R. R.

    1981-01-01

    Remote sensing of auroral X-rays from the topside can provide both local and global information concerning X-ray and energetic particle deposition within the middle atmosphere. Usually, contamination of X-ray detectors by corpuscular radiation can severely affect the scope and accuracy of the measurement. Preliminary results obtained with a rocket-borne instrument designed to operate cleanly in a precipitating particle environment are reported. Two dimensional images of the atmospheric bremsstrahlung X-ray sources were also constructed from the detector scan produced by payload translation and coning.

  5. Substorm effects in auroral spectra. [electron spectrum hardening

    NASA Technical Reports Server (NTRS)

    Eather, R. H.; Mende, S. B.

    1973-01-01

    A substorm time parameter is defined and used to order a large body of photometric data obtained on aircraft expeditions at high latitudes. The statistical analysis demonstrates hardening of the electron spectrum at the time of substorm, and it is consistent with the accepted picture of poleward expansion of aurora at the time of substorm and curvature drift of substorm-injected electrons. These features are not evident from a similar analysis in terms of magnetic time. We conclude that the substorm time concept is a useful ordering parameter for auroral data.

  6. The signature of auroral kilometric radiation on Isis 1 ionograms

    NASA Technical Reports Server (NTRS)

    Calvert, W.

    1981-01-01

    Auroral kilometric radiation (AKR) appears on the Isis 1 topside sounder ionograms as intense noise bands between the electron cyclotron frequency and 700 kHz. A variable gap occurs between the cyclotron frequency and the lowest AKR frequency. As Isis 1 traverses the source region, the gap narrows, and the AKR signals at higher frequencies weaken. This signature suggests that the AKR waves are generated directly in the extraordinary mode at frequencies just above the local cutoff frequency and that the radiation is initially perpendicular to the magnetic field.

  7. Temporal and Spatial Structure of Short Wavelength Infrared Auroral Backgrounds.

    DTIC Science & Technology

    1981-10-13

    measured when the auroral altitudes are sunlit (as reviewed in Section 5 of Reference 4). Navigating to compensate for winds and operating near the...measurements, no provision in the radar track could be made for the effects of winds on the aircraft. The aircraft was flown along a track which...00Slope. 1 7.5o*0.57 • efficiencyvo j-(U. I*o.o8)% 00SOO SI " (b) -jI.J. SlrAgo • . . • elope. o Solor Anole%9.9* .5051800 ilium. HeightsS9km ROOL76 /3

  8. Solar Array and Auroral Charging Studies of DMSP Spacecraft

    NASA Technical Reports Server (NTRS)

    Matias, Kelwin

    2013-01-01

    The SSJ electrostatic analyzers and the SSIES plasma instruments on the DMSP spacecraft in low Earth polar orbit can be used to conduct case studies of auroral and solar array charging. We will use a program written in the Interactive Data Language (IDL) to evaluate questionable charging events in the SSJ records by comparing charging signatures in SSJ and SSIES data. In addition, we will assemble a number of case studies of solar array charging showing the signatures from the SSJ data and compare to the SSIES charging signatures. In addition we will use Satellite Tool Kit (STK) to propagate orbits, obtain solar intensity, and use to verify onset of charging with sunrise.

  9. Energy of auroral electrons and Z mode generation

    NASA Technical Reports Server (NTRS)

    Krauss-Varban, D.; Wong, H. K.

    1990-01-01

    The present consideration of Z-mode radiation generation, in light of observational results indicating that the O mode and second-harmonic X-mode emissions can prevail over the X-mode fundamental radiation when suprathermal electron energy is low, gives attention to whether the thermal effect on the Z-mode dispersion can be equally important, and whether the Z-mode can compete for the available free-energy source. It is found that, under suitable circumstances, the growth rate of the Z-mode can be substantial even for low suprathermal auroral electron energies. Growth is generally maximized for propagation perpendicular to the magnetic field.

  10. Including auroral oval boundaries in the IRI model

    NASA Technical Reports Server (NTRS)

    Bilitza, A.

    1995-01-01

    At the last International Reference Ionosphere (IRI) Workshop it was decided that future editions of the model should include a representationof the aurroral oval boundaries. In this paper we review the different existing parameterizations of the auroral oval discussing their data base, boundary criteria, matematical formation, and overall usefulness for IRI. As a first candidate for incorporation into IRI we recomment the parameterization of the Feldstein ovals by Holzworth and Meng. Ways of implementing this model into IRI are discussed. We will also address adjustability with user-provided boundaries or boundary-related parameters, to better support strom-related studies.

  11. Spacecraft charging in the supra-auroral region

    SciTech Connect

    Rubin, A.G. )

    1989-12-01

    Electrostatic charging of spacecraft in electrostatic shock acceleration regions above the auroras is predicted to occur. Electrostatic shocks are thought to produce the electron streams which generate auroras. These electron streams can charge spacecraft to high potentials in the altitude range from 3,000 to 8,000 kilometers in the auroral region. Ion beams accelerated upward in electrostatic shocks contribute to charging as well. It is shown that the potential can be at most the maximum potential across the shock. Charging is altitude dependent within a shock.

  12. 24/7 Solar Minimum Polar Cap and Auroral Ion Temperature Observations

    NASA Technical Reports Server (NTRS)

    Sojka, Jan J.; Nicolls, Michael; van Eyken, Anthony; Heinselman, Craig; Bilitza, Dieter

    2011-01-01

    During the International Polar Year (IPY) two Incoherent Scatter Radars (ISRs) achieved close to 24/7 continuous observations. This presentation describes their data sets and specifically how they can provide the International Reference Ionosphere (IRI) a fiduciary E- and F-region ionosphere description for solar minimum conditions in both the auroral and polar cap regions. The ionospheric description being electron density, ion temperature and electron temperature profiles from as low as 90 km extending to several scale heights above the F-layer peak. The auroral location is Poker Flat in Alaska at 65.1 N latitude, 212.5 E longitude where the NSF s new Poker Flat Incoherent Scatter Radar (PFISR) is located. This location during solar minimum conditions is in the auroral region for most of the day but is at midlatitudes, equator ward of the cusp, for about 4-8 h per day dependent upon geomagnetic activity. In contrast the polar location is Svalbard, at 78.2 N latitude, 16.0 E longitude where the EISCAT Svalbard Radar (ESR) is located. For most of the day the ESR is in the Northern Polar Cap with a noon sector passage often through the dayside cusp. Of unique relevance to IRI is that these extended observations have enabled the ionospheric morphology to be distinguished between quiet and disturbed geomagnetic conditions. During the IPY year, 1 March 2007 - 29 February 2008, about 50 solar wind Corotating Interaction Regions (CIRs) impacted geospace. Each CIR has a two to five day geomagnetic disturbance that is observed in the ESR and PFISR observations. Hence, this data set also enables the quiet-background ionospheric climatology to be established as a function of season and local time. These two separate climatologies for the ion temperature at an altitude of 300 km are presented and compared with IRI ion temperatures. The IRI ion temperatures are about 200-300 K hotter than the observed values. However, the MSIS neutral temperature at 300 km compares favorably

  13. IAU Project and Research Activity in Nepal

    NASA Astrophysics Data System (ADS)

    Gautam, Suman

    2015-08-01

    The second half of the twentieth century has witnessed a tremendous development in the field of astronomy and space exploration. The large telescope both on the land and in the orbit, using the whole range of the electromagnetic spectra from radio waves to gamma rays are extending their range of exploration, right to the edge of the observable universe, and making astounding discoveries in the process. Many large international telescope facilities and global plans are accessible to all astronomers throughout the world, providing an inexpensive entry to cutting- edge international research for developing countries.Nepal is a mountainous country it has a wide range of climatic and altitude variations which varies from an elevation of 200 meter to ≥ 4000 meter. The average temperature varies from ≥ 25 o C to ≤ 0 to 5oC. Because of these diverse weather and climatic variation there is the potential for the establishment of sophisticated observatory/ data centre and link with each other. So, the future possible opportunity of astronomy in Nepal will be discussed. Besides Education and Research activities conducted in Tribhuvan University, Nepal under the support of International Astronomical Union (IAU) will also be highlighted. The importance brought by those two workshops conducted on data simulation supported by IAU under TF1 will also be discussed which is believed to play a vital role for the promotion and development of astronomy and astrophysics in developing countries.

  14. Relationship of Topside Ionospheric Ion Outflows to Auroral Forms and Precipitation, Plasma Waves, and Convection Observed by Polar

    NASA Technical Reports Server (NTRS)

    Hirahara, M.; Horwitz, J. L.; Moore, T. E.; Germany, G. A.; Spann, J. F.; Peterson, W. K.; Shelley, E. G.; Chandler, M. O.; Giles, B. L.; Craven, P. D.; Pollock, C. J.; Gurnett, D. A.; Pickett, J. S.; Persoon, A. M.; Scudder, J. D.; Maynard, N. C.; Mozer, F. S.; Brittnacher, M. J.; Nagai, T.

    1998-01-01

    The POLAR satellite often observes upflowing ionospheric ions (UFIs) in and near the aurora] oval on southern perigee (approx. 5000 km altitude) passes. We present the UFI features observed by the thermal ion dynamics experiment (TIDE) and the toroidal imaging mass angle spectrograph (TIMAS) in the dusk-dawn sector under two different geomagnetic activity conditions in order to elicit their relationships with auroral forms, wave emissions, and convection pattern from additional POLAR instruments. During the active interval, the ultraviolet imager (UVI) observed a bright discrete aurora on the duskside after the substorm onset and then observed a small isolated aurora form and diffuse auroras on the dawnside during the recovery phase. The UFIs showed clear conic distributions when the plasma wave instrument (PWI) detected strong broadband wave emissions below approx. 10 kHz, while no significant auroral activities were observed by UVI. At higher latitudes, the low-energy UFI conics gradually changed to the polar wind component with decreasing intensity of the broadband emissions. V-shaped auroral kilometric radiation (AKR) signatures observed above -200 kHz by PWI coincided with the region where the discrete aurora and the UFI beams were detected. The latitude of these features was lower than that of the UFI conics. During the observations of the UFI beams and conics, the lower-frequency fluctuations observed by the electric field instrument were also enhanced, and the convection directions exhibited large fluctuations. It is evident that large electrostatic potential drops produced the precipitating electrons and discrete auroras, the UFI beams, and the AKR, which is also supported by the energetic plasma data from HYDRA. Since the intense broadband emissions were also observed with the UFIs, the ionospheric ions could be energized transversely before or during the parallel acceleration due to the potential drops.

  15. Time development of high-altitude auroral acceleration region plasma, potentials, and field-aligned current systems observed by Cluster during a substorm

    NASA Astrophysics Data System (ADS)

    Hull, A. J.; Chaston, C. C.; Fillingim, M. O.; Mozer, F.; Frey, H. U.

    2013-12-01

    The auroral acceleration region is an integral link in the chain of events that transpire during substorms, and the currents, plasma and electric fields undergo significant changes driven by complex dynamical processes deep in the magnetotail. These auroral acceleration processes in turn accelerate and heat the plasma that ultimately leads to some of the most intense global substorm auroral displays. The complex interplay between field-aligned current system formation, the development of parallel electric fields, and resultant changes in the plasma constituents that occur during substorms within or just above the auroral acceleration zone remain unclear. We present Cluster multi-point observations within the high-altitude acceleration region (> 3 Re altitude) at key instances during the development of a substorm. Of particular emphasis is on the time-development of the plasma, potentials and currents that occur therein with the aim of ascertaining high-altitude drivers of substorm active auroral acceleration processes and auroral emission consequences. Preliminary results show that the initial onset is dominated by Alfvenic activity as evidenced by the sudden occurrence of relatively intense, short-spatial scale Alfvenic currents and attendant energy dispersed, counterstreaming electrons poleward of the growth-phase arc. The Alfvenic currents are locally planar structures with characteristic thicknesses on the order of a few tens of kilometers. In subsequent passages by the other spacecraft, the plasma sheet region became hotter and thicker via the injection of new hot, dense plasma of magnetospheric origins poleward of the pre-existing growth phase arc. In association with the heating and/or thickening of the plasma sheet, the currents appeared to broaden to larger scales as Alfven dominated activity gave way to either inverted-V dominated or mixed inverted-V and Alfvenic behavior depending on location. The transition from Alfven dominated to inverted-V dominated

  16. Update on U.S.EPA Cookstove Research Activities

    EPA Science Inventory

    The presentation includes background information on EPA's stove research, focuses on cookstove testing for air pollutant emissions and energy efficiency, and briefly describes current research activities. Ongoing activities are highlighted, and EPA contacts are provided.

  17. Characterizing magnetospheric electrons from ALIS observations of discrete auroral arcs and quasi-stationary modeling of auroral acceleration

    NASA Astrophysics Data System (ADS)

    Lamy, H.; Simon, C.; Echim, M.; de Keyser, J. M.; Gustavsson, B.; Sergienko, T.; Sandahl, I.; Brandstrom, U.

    2010-12-01

    From a series of images obtained simultaneously with the CCD cameras of the ALIS (Auroral Large Imaging System) network located in Scandinavia, three-dimensional (3D) large-scale structures of discrete auroral arcs can be retrieved in several filters with tomography-like techniques. In particular, the 3D reconstructed volume emission rates at 4278 Å can be used to derive the energy spectra of precipitating magnetospheric electrons in 2D, along and across the arc, with a spatial resolution of approximately 3 km. These spectra directly provide E0, the characteristic energy and ɛm, the total flux energy of precipitating electrons. The latter can be used together with a kinetic modelling of adiabatic motion of particles (Lundin & Sandahl, 1978) and assuming a Maxwellian distribution for magnetospheric electrons, to derive ΔΦ, the field-aligned potential difference between the ionosphere and magnetosphere. The next step is to use a quasi-static magnetosphere-ionosphere coupling model based on the current continuity in the ionosphere (Echim et al, 2007) and the model of tangential discontinuity generators (Roth et al 1993) to determine densities (ne) and temperatures (Te) of the magnetospheric electrons. The model is run iteratively for typical values of magnetospheric ne and Te that are adjusted until ΔΦ provided by the model is in agreement with the one determined from ALIS observations. This technique allows to obtain information about the properties of the generator of the auroral arc, from ground-based observations and quasi-stationary modeling. Future conjugated observations between ALIS and a spacecraft crossing the same magnetic field lines above the acceleration region could be used to validate this novel technique.

  18. The spatial relationship of field-aligned currents and auroral electrojets to the distribution of nightside auroras

    NASA Technical Reports Server (NTRS)

    Kamide, Y.; Rostoker, G.

    1977-01-01

    An analysis is made of (1) nearly simultaneous sets of data obtained by a ground-based magnetometer, (2) magnetic perturbations recorded by the polar-orbiting Triad satellite at 800 km, (3) auroral imagery, and (4) studies made of precipitating electrons within the 200 eV to 20 keV range. The analysis is used to determine periods of moderate magnetospheric activity during which substorms occur. Results are presented with attention to morning sector, evening sector, premidnight substorm, and midnight sector features.

  19. The thermospheric auroral red line polarization: confirmation of detection and first quantitative analysis

    NASA Astrophysics Data System (ADS)

    Lilensten, Jean; Barthelemy, Mathieu; Lamy, Hervé; Simon, Cyril; Bommier, Véronique; Amblard, Pierre-Olivier; Moen, Joran; Rothkaehl, Hanna

    2013-04-01

    The thermospheric atomic oxygen red line is among the brightest in the auroral spectrum. Previous obser- vations in Longyearbyen, Svalbard indicated that it may be intrinsically polarized but a possible contamination by light pollution could not be ruled out. During the winter 2010 / 2011, the polarization of the red line was measured for the first time at the Polish Hornsund polar base without contam- ination. Two methods of data analysis are presented to com- pute the degree of linear polarization (DoLP) and angle of linear polarization (AoLP): one is based on averaging and the other one on filtering. Results are compared and are in qualitative agreement. For solar zenith angles (SZA) larger than 108° (with no contribution from Rayleigh scattering), the DoLP ranges between 2 and 7%. The AoLP is more or less aligned with the direction of the magnetic field line in agreement with the theoretical predictions of Bommier et al. (2010). However, the AoLP values range between ± 20° around this direction, depending on the auroral conditions. Correlations between the polarization parameters and the red line intensity I were considered. The DoLP decreases when I increases, confirming a trend observed during the obser- vations in Longyearbyen. However, for small values of I, DoLP varies within a large range of values, while for large values of I, DoLP is always small. The AoLP also varies with the red line intensity, slightly rotating around the mag- netic field line. The present research project has been supported by the French Polar Institute (IPEV No 1026) and by the European project COST ES0803 "Developing space weather products and services in Europe". It is also part of the European project COST MP1104 "Polarization as a tool to study the Solar System and beyond" and the European FP7 Project ESPAS, Grant agreement no: 283676.

  20. The Jovian Auroral Distributions Experiment (JADE) on the Juno Mission to Jupiter

    NASA Astrophysics Data System (ADS)

    McComas, D. J.; Alexander, N.; Allegrini, F.; Bagenal, F.; Beebe, C.; Clark, G.; Crary, F.; Desai, M. I.; De Los Santos, A.; Demkee, D.; Dickinson, J.; Everett, D.; Finley, T.; Gribanova, A.; Hill, R.; Johnson, J.; Kofoed, C.; Loeffler, C.; Louarn, P.; Maple, M.; Mills, W.; Pollock, C.; Reno, M.; Rodriguez, B.; Rouzaud, J.; Santos-Costa, D.; Valek, P.; Weidner, S.; Wilson, P.; Wilson, R. J.; White, D.

    2013-05-01

    The Jovian Auroral Distributions Experiment (JADE) on Juno provides the critical in situ measurements of electrons and ions needed to understand the plasma energy particles and processes that fill the Jovian magnetosphere and ultimately produce its strong aurora. JADE is an instrument suite that includes three essentially identical electron sensors (JADE-Es), a single ion sensor (JADE-I), and a highly capable Electronics Box (EBox) that resides in the Juno Radiation Vault and provides all necessary control, low and high voltages, and computing support for the four sensors. The three JADE-Es are arrayed 120∘ apart around the Juno spacecraft to measure complete electron distributions from ˜0.1 to 100 keV and provide detailed electron pitch-angle distributions at a 1 s cadence, independent of spacecraft spin phase. JADE-I measures ions from ˜5 eV to ˜50 keV over an instantaneous field of view of 270∘×90∘ in 4 s and makes observations over all directions in space each 30 s rotation of the Juno spacecraft. JADE-I also provides ion composition measurements from 1 to 50 amu with m/Δm˜2.5, which is sufficient to separate the heavy and light ions, as well as O+ vs S+, in the Jovian magnetosphere. All four sensors were extensively tested and calibrated in specialized facilities, ensuring excellent on-orbit observations at Jupiter. This paper documents the JADE design, construction, calibration, and planned science operations, data processing, and data products. Finally, the Appendix describes the Southwest Research Institute [SwRI] electron calibration facility, which was developed and used for all JADE-E calibrations. Collectively, JADE provides remarkably broad and detailed measurements of the Jovian auroral region and magnetospheric plasmas, which will surely revolutionize our understanding of these important and complex regions.

  1. Consumer involvement in research projects: the activities of research funders.

    PubMed

    O'Donnell, Máire; Entwistle, Vikki

    2004-08-01

    This paper reports findings from a postal questionnaire survey and in-depth interviews with UK funders of health-related research that explored whether, why and how they promote consumer involvement in research projects. Many UK funders of health-related research are adopting a policy of promoting consumer involvement in research projects. Telephone interviews revealed they have several reasons for doing so, and that they vary in the ways they encourage and support researchers to involve consumers. For some, descriptions of consumer involvement in a research proposal are important for project funding decisions. They recognized a need for flexibility when assessing consumer involvement in different contexts. We suggest that funders should continue to work to clarify what they consider to be the parameters of acceptability in terms of consumer involvement and ensure that 'flexible' criteria are fairly applied. Researchers should be aware of particular funders' views when applying for project funding.

  2. 20 CFR 401.165 - Statistical and research activities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Statistical and research activities. 401.165... RECORDS AND INFORMATION Disclosure of Official Records and Information § 401.165 Statistical and research activities. (a) General. Statistical and research activities often do not require information in a...

  3. 20 CFR 401.165 - Statistical and research activities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Statistical and research activities. 401.165... RECORDS AND INFORMATION Disclosure of Official Records and Information § 401.165 Statistical and research activities. (a) General. Statistical and research activities often do not require information in a...

  4. 20 CFR 401.165 - Statistical and research activities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Statistical and research activities. 401.165... RECORDS AND INFORMATION Disclosure of Official Records and Information § 401.165 Statistical and research activities. (a) General. Statistical and research activities often do not require information in a...

  5. 20 CFR 401.165 - Statistical and research activities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Statistical and research activities. 401.165... RECORDS AND INFORMATION Disclosure of Official Records and Information § 401.165 Statistical and research activities. (a) General. Statistical and research activities often do not require information in a...

  6. 20 CFR 401.165 - Statistical and research activities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Statistical and research activities. 401.165... RECORDS AND INFORMATION Disclosure of Official Records and Information § 401.165 Statistical and research activities. (a) General. Statistical and research activities often do not require information in a...

  7. Low-altitude satellite measurements of pulsating auroral electrons

    NASA Astrophysics Data System (ADS)

    Samara, M.; Michell, R. G.; Redmon, R. J.

    2015-09-01

    We present observations from the Defense Meteorological Satellite Program and Reimei satellites, where common-volume high-resolution ground-based auroral imaging data are available. These satellite overpasses of ground-based all-sky imagers reveal the specific features of the electron populations responsible for different types of pulsating aurora modulations. The energies causing the pulsating aurora mostly range from 3 keV to 20 keV but can at times extend up to 30 keV. The secondary, low-energy electrons (<1 keV) are diminished from the precipitating distribution when there are strong temporal variations in auroral intensity. There are often persistent spatial structures present inside regions of pulsating aurora, and in these regions there are secondary electrons in the precipitating populations. The reduction of secondary electrons is consistent with the strongly temporally varying pulsating aurora being associated with field-aligned currents and hence parallel potential drops of up to 1 kV.

  8. Duration and Extent of the Great Auroral Storm of 1859

    NASA Technical Reports Server (NTRS)

    Green, James L.; Boardsen, Scott

    2005-01-01

    The great geomagnetic storm of August 28 through September 3,1859 is, arguably, the greatest and most famous space weather event in the last two hundred years. For the first time observations showed that the sun and aurora were connected and that auroras generated strong ionospheric currents. A significant portion of the world's 200,000 km of telegraph lines were adversely affected, many of which were unusable for 8 hours or more which had a real economic impact. In addition to published scientific measurements, newspapers, ship logs, and other records of that era provide an untapped wealth of first hand observations giving time and location along with reports of the auroral forms and colors. At its height, the aurora was described as a blood or deep crimson red that was so bright that one "could read a newspaper by." At its peak, the Type A red aurora lasted for several hours and was observed to reach extremely low geomagnetic latitudes on August 28-29 (-25") and on September 2-3 (-18"). Auroral forms of all types and colors were observed below 50" latitude for -24 hours on August 28-29 and -42 hours on September 2-3. From a large database of ground-based observations the extent of the aurora in corrected geomagnetic coordinates is presented over the duration of the storm event.

  9. Application of X-ray imaging techniques to auroral monitoring

    NASA Technical Reports Server (NTRS)

    Rust, D. M.; Burstein, P.

    1981-01-01

    The precipitation of energetic particles into the ionosphere produces bremsstrahlung X-rays and K-alpha line emission from excited oxygen and nitrogen. If viewed from a spacecraft in a highly elliptical polar orbit, this soft (0.3 - 3.0 keV) X-radiation will provide an almost uninterrupted record of dayside and nightside auroras. A grazing incidence X-ray telescope especially designed for such auroral monitoring is described. High photon collection efficiency will permit exposure times of approximately 100 seconds during substorms. Spectrophotometry will allow users to derive the energy spectrum of the precipitating particles. If placed in a 15 earth-radius orbit, the telescope can produce auroral X-ray images with 30 km resolution. Absolute position of X-ray auroras can be established with a small optical telescope co-aligned with the X-ray telescope. Comparison of X-ray and optical images will establish the height and global distribution of X-ray aurorae, relative to well-known optical auroras, thus melding the new X-ray results with knowledge of optical auroras.

  10. AURORAL RADIO EMISSION FROM STARS: THE CASE OF CU VIRGINIS

    SciTech Connect

    Trigilio, Corrado; Leto, Paolo; Umana, Grazia; Buemi, Carla S.; Leone, Francesco

    2011-09-20

    CU Virginis is a rapidly rotating Magnetic Chemically Peculiar star with at present unique characteristics as a radio emitter. The most intriguing one is the presence of intense, 100% circularly polarized radiation ascribed to a cyclotron maser. Each time the star rotates, this highly beamed emission points two times toward the Earth, like a pulsar. We observed CU Vir in 2010 April with the Expanded Very Large Array in two bands centered at 1450 and 1850 MHz. We covered nearly the whole rotational period, confirming the presence of the two pulses at a flux density up to 20 mJy. Dynamical spectra, obtained with unprecedented spectral and temporal sensitivity, allow us to clearly see the different time delays as a function of frequency. We interpret this behavior as a propagation effect of the radiation inside the stellar magnetosphere. The emerging scenario suggests interesting similarities with the auroral radio emission from planets, in particular with the Auroral Kilometric Radiation from Earth, which originates at few terrestrial radii above the magnetic poles and was only recently discovered to be highly beamed. We conclude that the magnetospheres of CU Vir, Earth, and other planets, maybe also exoplanets, could have similar geometrical and physical characteristics in the regions where the cyclotron maser is generated. In addition, the pulses are perfect 'markers' of the rotation period. This has given us for the first time the possibility to measure with extraordinary accuracy the spin-down of a star on or near the main sequence.

  11. Global auroral imaging instrumentation for the Dynamics Explorer Mission

    NASA Technical Reports Server (NTRS)

    Frank, L. A.; Craven, J. D.; Ackerson, K. L.; English, M. R.; Eather, R. H.; Carovillano, R. L.

    1981-01-01

    The instrumentation for obtaining global images of the auroral oval from the high-altitude spacecraft of the Dynamics Explorer Mission is described. It is noted that the three spin-scan auroral imaging photometers are expected to be able to effectively view the dim emissions from earth in the presence of strong stray light sources near their fields-of-view along the sunlit portion of the spacecraft orbit. A special optical design that includes an off-axis parabolic mirror as the focusing element and super-reflecting mirror surfaces is used to minimize the effects of stray light. The rotation of the spacecraft and an instrument scanning mirror provide the two-dimensional array of pixels making up an image frame. It is pointed out that the full width of the fields-of-view of the photometers corresponding to a single pixel is 0.29 deg and that the angular dimensions of a typical full frame are 30 deg x 30 deg and span 14,400 pixels.

  12. The effect of parallel currents on auroral micropulsations

    NASA Technical Reports Server (NTRS)

    Tavares, M.; Roth, I.; Vinas, A. F.

    1994-01-01

    Field aligned currents play an important role in the global coupling between the magnetosphere and the ionosphere and in their relationship to the auroral phenomena. Moreover, there exists evidence that resonant oscillations are related to large-scale Birkeland currents. The spatial confinement of the field-aligned currents forms an inhomogeneous system susceptible to low-frequency oscillations, which can be excited due to periodic variations in the solar wind pressure or to the Kelvin-Helmholtz (KH) instability. In this paper we present a study of ultralow-frequency (ULF) oscillations in an inhomogeneous magnetic field formed by a large-scale current. We investigate the effects of the field-aligned currents on the generation of localized Alfven waves. The field oscillations are described by an eigenvalue wave equation which includes the effects of the field aligned currents and which produces a discrete spectrum of Alfven waves. These waves are observed mainly in three regions of the magnetosphere: in the magnetosheath, in the polar cusp, and in the plasmasphere. In the present study we limit our investigation to the auroral region.

  13. Low-Altitude Satellite Measurements of Pulsating Auroral Electrons

    NASA Technical Reports Server (NTRS)

    Samara, M.; Michell, R. G.; Redmon, R. J.

    2015-01-01

    We present observations from the Defense Meteorological Satellite Program and Reimei satellites, where common-volume high-resolution ground-based auroral imaging data are available. These satellite overpasses of ground-based all-sky imagers reveal the specific features of the electron populations responsible for different types of pulsating aurora modulations. The energies causing the pulsating aurora mostly range from 3 keV to 20 keV but can at times extend up to 30 keV. The secondary, low-energy electrons (<1 keV) are diminished from the precipitating distribution when there are strong temporal variations in auroral intensity. There are often persistent spatial structures present inside regions of pulsating aurora, and in these regions there are secondary electrons in the precipitating populations. The reduction of secondary electrons is consistent with the strongly temporally varying pulsating aurora being associated with field-aligned currents and hence parallel potential drops of up to 1 kV.

  14. Rocket-borne wave measurements in the dayside auroral oval

    NASA Technical Reports Server (NTRS)

    Temerin, M.; Kelley, M. C.

    1980-01-01

    VLF and ELF waves were measured on two rocket payloads launched into the dayside auroral oval on Dec. 18, 1974, and on Jan. 11, 1975. The correlation of the VLF hiss intensity with the fluxes of precipitating electrons above 500 eV on short spatial and time scales was often poor, even when a positive slope existed in the electron phase space density. During the flight in 1975, distinct features were observed at the lower hybrid frequency; the frequency of this emission was used together with an independent density measurement to determine the relative concentration of O(+) to the heavier ions NO(+) and O2(+). It was found that the density of NO(+) or O2(+), which could not be distinguished, is enhanced over expected values between 150 and 400 km altitude. Broadband electrostatic and electromagnetic waves were observed after the barium-shaped charged explosion in 1975; the observed lowering of the auroral VLF hiss cutoff due to the barium is consistent with either ducting of VLF hiss emissions along the enhanced density duct produced by the barium or with local generation VLF hiss during the barium injection.

  15. Duration and extent of the great auroral storm of 1859

    PubMed Central

    Green, James L.; Boardsen, Scott

    2016-01-01

    The great geomagnetic storm of August 28 through September 3, 1859 is, arguably, the greatest and most famous space weather event in the last two hundred years. For the first time observations showed that the sun and aurora were connected and that auroras generated strong ionospheric currents. A significant portion of the world’s 200,000 km of telegraph lines were adversely affected, many of which were unusable for 8 h or more which had a real economic impact. In addition to published scientific measurements, newspapers, ship logs, and other records of that era provide an untapped wealth of first hand observations giving time and location along with reports of the auroral forms and colors. At its height, the aurora was described as a blood or deep crimson red that was so bright that one “could read a newspaper by.” At its peak, the Type A red aurora lasted for several hours and was observed to reach extremely low geomagnetic latitudes on August 28–29 (~25°) and on September 2–3 (~18°). Auroral forms of all types and colors were observed below 50° latitude for ~24 h on August 28–29 and ~42 h on September 2–3. From a large database of ground-based observations the extent of the aurora in corrected geomagnetic coordinates is presented over the duration of the storm event. PMID:28066122

  16. A pulsating auroral X-ray hot spot on Jupiter.

    PubMed

    Gladstone, G R; Waite, J H; Grodent, D; Lewis, W S; Crary, F J; Elsner, R F; Weisskopf, M C; Majeed, T; Jahn, J-M; Bhardwaj, A; Clarke, J T; Young, D T; Dougherty, M K; Espinosa, S A; Cravens, T E

    2002-02-28

    Jupiter's X-ray aurora has been thought to be excited by energetic sulphur and oxygen ions precipitating from the inner magnetosphere into the planet's polar regions. Here we report high-spatial-resolution observations that demonstrate that most of Jupiter's northern auroral X-rays come from a 'hot spot' located significantly poleward of the latitudes connected to the inner magnetosphere. The hot spot seems to be fixed in magnetic latitude and longitude and occurs in a region where anomalous infrared and ultraviolet emissions have also been observed. We infer from the data that the particles that excite the aurora originate in the outer magnetosphere. The hot spot X-rays pulsate with an approximately 45-min period, a period similar to that reported for high-latitude radio and energetic electron bursts observed by near-Jupiter spacecraft. These results invalidate the idea that jovian auroral X-ray emissions are mainly excited by steady precipitation of energetic heavy ions from the inner magnetosphere. Instead, the X-rays seem to result from currently unexplained processes in the outer magnetosphere that produce highly localized and highly variable emissions over an extremely wide range of wavelengths.

  17. Auroral hot-ion dynamo model with finite gyroradii

    SciTech Connect

    Lennartsson, O. W.

    2006-07-15

    Discrete auroras have (1) narrow size s(less-or-similar sign)30 km in at least one dimension (e.g., north-south) and (2) often rapid variation of forms, especially where the size is extremely small, s{<=}1 km. These points mesh with spatial and temporal features observed at several Earth radii in earthward flows (bursts) of hot plasma along high-latitude geomagnetic field lines. The flows (include PSBL) usually have some filamentary structure with transverse widths of a few local gyroradii of the hot protons (kT{approx}1-30 keV), i.e., widths that encompass auroral-arc size when scaled by magnetic field-line separation. At these widths, modest density gradients ({delta}n{approx}0.01-0.1 cm{sup -3}) lead to charge separation by differential mirroring of hot protons and electrons and large perpendicular electric fields. Thermal escape of ionspheric electrons into positive charge layer builds up magnetic field-aligned potential difference that accelerates hot electrons from negative charge layer into the ionosphere within auroral arc thickness. As a corollary, the model delineates a mechanism for charge-driven plasma instabilities.

  18. Duration and extent of the great auroral storm of 1859.

    PubMed

    Green, James L; Boardsen, Scott

    2006-01-01

    The great geomagnetic storm of August 28 through September 3, 1859 is, arguably, the greatest and most famous space weather event in the last two hundred years. For the first time observations showed that the sun and aurora were connected and that auroras generated strong ionospheric currents. A significant portion of the world's 200,000 km of telegraph lines were adversely affected, many of which were unusable for 8 h or more which had a real economic impact. In addition to published scientific measurements, newspapers, ship logs, and other records of that era provide an untapped wealth of first hand observations giving time and location along with reports of the auroral forms and colors. At its height, the aurora was described as a blood or deep crimson red that was so bright that one "could read a newspaper by." At its peak, the Type A red aurora lasted for several hours and was observed to reach extremely low geomagnetic latitudes on August 28-29 (~25°) and on September 2-3 (~18°). Auroral forms of all types and colors were observed below 50° latitude for ~24 h on August 28-29 and ~42 h on September 2-3. From a large database of ground-based observations the extent of the aurora in corrected geomagnetic coordinates is presented over the duration of the storm event.

  19. Quantitative patterns of large-scale field-aligned currents in the auroral ionosphere

    SciTech Connect

    Foster, J.C.; Fuller-Rowell, T.; Evans, D.S.

    1989-03-01

    Quantitative patterns of the distribution of field-aligned current (FAC) density have been derived from gradients of the average patterns of the Hall and Pedersen currents at high latitudes under the assumption that the total current is divergence-free. The horizontal currents were calculated from empirical convection electric field models, derived from Millstone Hill radar observations, and the ionospheric Hall and Pedersen conductances, based on satellite observations of the precipitating particle energy flux and spectrum and including an average (equinox) solar contribution. These independent empirical models, and the resultant patterns of the field-aligned currents, are keyed to an auroral precipitation index which quantifies the intensity and spatial extent of high-latitude particle precipitation and which is determined from a single satellite crossing of the auroral precipitation pattern. The patterns detail the spatial distribution of the currents as a function of increasing disturbance level. The magnitudes of the total single-hemisphere currents into or out of the ionosphere are closely balanced at each activity level and increase exponentially between 0.1 and 6 MA with increasing values of the precipitation index. The interplanetary magnetic field (IMF) sector dependence of the FAC patterns is investigated for disturbed conditions. A large portion of the FAC pattern is closed by local Pedersen currents (current into the ionosphere is balanced by an equal current out of the ionosphere at that local time). This locally balanced portion of the FAC system is enhanced in the prenoon (postnoon) sector for IMF B/sub v/>+1 nT (B/sub y/<-1 nT). In addition, there are net currents into the ionosphere postnoon and out of the ionosphere in the premidnight sector.

  20. Results of the Jupiter Infrared Auroral Mapper from the Juno Earth fly-by

    NASA Astrophysics Data System (ADS)

    Adriani, A.; Mura, A.; Filacchione, G.; Di Iorio, T.; Turrini, D.; Noschese, R.; Cicchetti, A.; Grassi, D.; Sindoni, G.; Zambelli, M.; Piccioni, G.; Capria, M. T.; Tosi, F.; Orosei, R.; Dinelli, B. M.; Moriconi, M. L.; Lunine, J. I.

    2013-12-01

    The InfraRed Auroral Mapper (JIRAM) is simultaneously an imager and a spectrometer on board of the Juno mission. Jupiter's reflected and emitted light in the range 2-5 μm can be sensed through its spectral channel and H3+ emissions analyzed to retrieve auroral parameters. JIRAM is also able to map the infrared Jupiter aurora in the 3.5 μm and planet's thermal emissions in the 5 μm wavelength ranges through its L-band and M-band imager filters . The main scientific goals are the study of auroras, hot spots and other Jupiter atmospheric structures detectable in its working spectral range. Concurrently with the Juno Earth fly-by, that will occur on October 9th of this current year, JIRAM will observe the Moon during its transit approaching the Earth. As the instrument's temperature cannot be actively controlled, operating with a passive cooling system, the Earth will not be observed during the closest approach. A dramatic temperature increase of the instrument, far above its performance limit, is expected in fact by the illumination of the instrument's cooling radiators due to our planet reflection of the solar illumination. The Moon will be the only chance for an extended target observation that JIRAM can experience before Jupiter. Consequently, this opportunity is of pivotal importance being the only chance for a real in-flight test to verify the instrument performances and the radiometric calibration in real observational set up. The instrument will be operated in the same functional configuration that it will use at Jupiter. So far, the only absolute radiometric calibration has been performed in lab during the on ground calibration and functional test sessions. The internal calibration unit is mainly devoted to the spectral calibration checking while the absolute radiometric calibration has to verified and confirmed in flight. Results of lunar observations will be presented.

  1. Updated modeling of Io and non-Io Radio Auroral Emissions of Jupiter

    NASA Astrophysics Data System (ADS)

    Louis, C.; Lamy, L.; Zarka, P.; Cecconi, B.; Hess, S.

    2015-10-01

    The radio auroral emissions produced by the Jupiter's magnetosphere between a few kHz and 40MHz, the most intense of our Solar System, are known since half a century, but they still drive many questions, and their deepened study is one of the main aim of the JUNO missions (arrival in July 2016). Jovian auroral radio emissions are thought to be produced through the Cyclotron Maser Instability (CMI), from non-maxwellian weakly relativistic electrons gyrating along high-latitude magnetic fields lines (Zarka, 1998). These emissions divide in different spectral components, driven or not by the moon Io. The origin and the relationship between kilometric, hectometric and decametric non-Io emissions in particular remains poorly understood. To investigate these emissions, we simulated numerical dynamic spectra with the most recent version of the ExPRES code - Exoplanetary and Planetary Radio Emission Simulator, available at http://maser.obspm.fr - already used to successfully model Io decametric and Saturn's kilometric arcshaped emissions (Hess et al., 2008, Lamy et al., 2008) and predict exoplanetary radio emissions (Hess et al., 2011). Such simulations bring direct constraints on the locus of active magnetic field lines and on the nature of CMI-unstable electrons (Hess et al., submitted). We validated the new theoretical calculation of the beaming angle used by ExPRES, which now includes refraction at the source. We then built updated simulations of Io and non-Io emissions which were compared to the radio observations acquired by the Cassini spacecraft (Jupiter flyby in 2000) and the Nançay decameter array (routines observations of Jupiter).

  2. The Calibration of a Large Number of Scientific Instruments for the Auroral Spatial Structures Probe Sub-Orbital Mission.

    NASA Astrophysics Data System (ADS)

    Swenson, A.; Miller, J.; Neilsen, T. L.; Fish, C. S.; Swenson, C.

    2014-12-01

    The Auroral Spatial Structures Probe (ASSP) is a NASA sounding rocket mission to be launched in the early January 2015 time frame from the Poker Flat Research Range. The primary scientific objective of this mission is to determine the contribution of small spatial and temporal scale fluctuations of the electric fields to the larger-scale processes during active aurora. This will be accomplished through the use of a constellation of six small payloads ejected at high velocity from a sounding rocket. The multiple baseline observations of the electric and magnetic fields will be used to observe variability of both the E-field and the Poynting flux. These observations will be placed in the context of available data, including winds, large scale E-fields, and proxy conductivity (airglow images) observations.Each sub-payload will carry a crossed pair of electric field double-probe sensors, a three-axis magnetometer, and a Langmuir probe. In total there are eight of each instrument type requireing calibration. Since the instruments need to be calibrated over temperature a full calibration of a single instrument is very time-consuming. The decision was made to automate the calibration process. Measurements were taken using a relay switch-box connecting the instruments to test sources. Calibration data were saved into a database. Using post-processing scripts on these databases a calibration for each instrument at each temperature point was made. This approach is a prototype process that might be used for calibrating a large constellation of CubeSats with similar instruments. In this poster we review the ASSP science and mission, and the results of the pre-flight calibration of the science instruments.

  3. Quasi-periodic (~mHz) dayside auroral brightennings associated with high-speed solar wind

    NASA Astrophysics Data System (ADS)

    Liou, K.

    2013-12-01

    It has been reported that dayside auroral pulsations of a few mHz frequency can occur when variations of solar wind dynamic pressure at the same frequency appear. Magnetospheric compression/decompression is attributed to the auroral pulsations. Here we report another type of dayside auroral pulsations not associated with solar wind dynamic pressure changes by using global auroral images acquired from the Ultraviolet Imager (UVI) on board the Polar satellite. From one periodic (~2 - 8 mHz) auroral event that occurred on February 8, 2000, it is found that the auroral enhancements covered most of the day (~05 - 16 MLT) sector and did not show a latitudinal dependence. Based on in situ particle data from DMSP SSJ/4, the brightennings were associated mainly with enhanced particle precipitations from the central plasma sheet (i.e., diffuse aurora). There was no geomagnetic pulsation on the ground and in the dawn sector of the magnetosheath as indicated by the Geotail measurements. While the auroral pulsations occurred during high solar wind speed (> 600 km/s), they commenced when the interplanetary magnetic field turned northward, suggesting the Kelvin-Helmholtz instability being a source of the pulsations. We will present detail analysis results and discuss other possible mechanisms in the context of current theories.

  4. Predicting Electron Energy Flux Using Ground-Based Multi-Spectral Auroral Imaging

    NASA Astrophysics Data System (ADS)

    Grubbs, G. A.; Samara, M.; Michell, R.; Redmon, R. J.

    2013-12-01

    High-resolution, multi-spectral auroral observations can now be routinely acquired using the Multi-spectral Observatory Of Sensitive EMCCDs (MOOSE), currently installed in Poker Flat, AK. Observations from the past 2 auroral seasons have yielded many simultaneous auroral observations in 4 different emission lines (427.8 nm, 557.7 nm, 630 nm, and 844.6 nm). From these data, the brightness of the absolute auroral emissions will be calculated. Combined with atmospheric modeling, auroral emission brightness will be used to predict the total energy flux and characteristic energy of the electrons responsible for the aurora. The theory behind this method is only developed for auroral measurements in the magnetic zenith, and therefore it is not known to what extent it can be applied off zenith. All-sky auroral image data will be examined and compared with DMSP satellite overpasses to quantify the extent to which the model can make predictions off-zenith, creating an empirical model that could then be applied to the many cases without overpasses. This will lead to large-scale 2-D maps of electron precipitation characteristics which can contribute to global ionospheric models.

  5. A superposed epoch analysis of auroral evolution during substorms: Local time of onset region

    NASA Astrophysics Data System (ADS)

    Milan, S. E.; Grocott, A.; Hubert, B.

    2010-10-01

    Previous workers have shown that the magnetic local time (MLT) of substorm onset depends on the prevailing east-west component of the interplanetary magnetic field (IMF). To investigate the influence of the onset MLT on the subsequent auroral response we perform a superposed epoch analysis of the auroral evolution during approximately 2000 substorms using observations from the FUV instrument on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft. We subdivide the substorms by onset latitude and onset local time before determining average auroral images before and after substorm onset, for both electron and proton aurorae. We find that during the growth phase there is preexisting auroral emission in the MLT sector of the subsequent onset. After onset the auroral bulge expands eastward and westward, but remains centered on the onset sector. Approximately 30 min after onset, during the substorm recovery phase, the peaks in electron and proton auroral emission move into the postnoon and prenoon sectors, respectively, reflecting the “average” auroral precipitation patterns determined by previous studies. Superposed epoch analysis of the interplanetary magnetic field for the substorms under study suggests that the BY component of the IMF must be biased toward positive or negative values for up to a day prior to onset for the onset MLT to be influenced.

  6. Artificial periodic irregularities in the auroral ionosphere

    NASA Astrophysics Data System (ADS)

    Rietveld, M. T.; Turunen, E.; Matveinen, H.; Goncharov, N. P.; Pollari, P.

    1996-12-01

    is larger above 60 km by a factor of up to 2 at 64 km. The comparisons with the model are considered to be a good basis for more refined comparisons. Acknowledgements. This work has been supported by the UK Particle-Physics and Astronomy Research Council. The assistance of the director and staff of the EISCAT Scientific Association, the staff of the Norsk Polarinstitutt and the director and staff of the Swedish Institute of Space Physics is gratefully acknowledged. In addition the authors would like to thank Professor Evgeny Tereshchenko of the Polar Geophysical Institute in Mumansk, Russia and Dr Tuomo Nygrén of the University of Oulu, Finland for provision of data from EISCAT special program time during the November 1995 campaign. Topical Editor D. Alcaydé thanks E. J. Fremouw and another referee for their help in evaluating this paper.--> Correspondence to: I. K. Walker-->

  7. Development of the Near-Earth Magnetotail and the Auroral Arc Associated with Substorm Onset: Evidence for a New Model

    NASA Astrophysics Data System (ADS)

    Miyashita, Y.; Hiraki, Y.; Angelopoulos, V.; Ieda, A.; Machida, S.

    2015-12-01

    We have studied the time sequence of the development of the near-Earth magnetotail and the auroral arc associated with a substorm onset, using the data from the THEMIS spacecraft and ground-based observatories at high temporal and spatial resolutions. We discuss four steps of the auroral development, linking them to magnetotail changes: the auroral fading, the initial brightening of an auroral onset arc, the enhancement of the wave-like structure, and the poleward expansion. A case study shows that near-Earth magnetic reconnection began at X~-17 RE at least ~3 min before the auroral initial brightening and ~1 min before the auroral fading. Ionospheric large-scale convection also became enhanced just before the auroral fading and before the auroral initial brightening. Then low-frequency waves were amplified in the plasma sheet at X~-10 RE, with the pressure increase due to the arrival of the earthward flow from the near-Earth reconnection site ~20 s before the enhancement of the auroral wave-like structure. Finally, the dipolarization began ~30 s before the auroral poleward expansion. On the basis of the present observations, we suggest that near-Earth magnetic reconnection plays two roles in the substorm triggering. First, it generates a fast earthward flow and Alfvén waves. When the Alfvén waves which propagate much faster than the fast flow reach the ionosphere, large-scale ionospheric convection is enhanced, leading to the auroral initial brightening and subsequent gradual growth of the auroral wave-like structure. Second, when the reconnection-initiated fast flow reaches the near-Earth magnetotail, it promotes rapid growth of an instability, such as the ballooning instability, and the auroral wave-like structure is further enhanced. When the instability grows sufficiently, the dipolarization and the auroral poleward expansion are initiated.

  8. Further study of flickering auroral roar emission: 1. South Pole observations

    NASA Astrophysics Data System (ADS)

    Ye, S.; Labelle, J.; Weatherwax, A. T.

    2006-07-01

    Hughes and LaBelle (2001) reported a single example of a new geophysical phenomenon: ˜10 Hz modulation of auroral radio emissions near twice the auroral ionospheric electron gyrofrequency. They called this phenomenon flickering auroral roar and suggested that it is related to flickering aurora, which results from ˜10 Hz modulation of the precipitating auroral electrons. Observations at South Pole Station during 2003 using a new high-bandwidth receiving system have yielded 10 examples of flickering roar emissions. Although 10 examples is still a small number for statistics, these observations considerably extend previous knowledge of this phenomenon which was based on a single example. On the basis of the 2003 South Pole data set, flickering auroral roar accounts for only about 1-2% of auroral roar in number of seconds, but ˜20% of auroral roar events have some flickering feature. The observed modulation frequencies range from ˜3 to 30 Hz. The 10- to 20-Hz modulations, which correspond to about 65% of the time when flickering roar occurs, are much more common than the higher-frequency 20- to 30-Hz modulations, which correspond to about 20% of the time when flickering roar occurs. These frequencies compare favorably with optical observations of auroral emissions, rocket observations of electron flux modulations, and modeling results. If these frequencies correspond to the oxygen gyrofrequency where electrons and ion cyclotron waves interact, the 3- to 30-Hz frequency range would imply sources at altitudes of 1500-10,500 km. Six of the ten flickering roar examples occurred during substorm expansion phase as defined from local magnetometer data, in contrast to flickering aurora, which is usually observed after the onset of auroral breakup.

  9. Action Research as a Professional Development Activity

    ERIC Educational Resources Information Center

    West, Chad

    2011-01-01

    Reflective teachers are always searching for ways to improve their teaching. When this reflection becomes intentional and systematic, they are engaging in teacher research. This type of research, sometimes called "action research", can help bridge the gap between theory and practice by addressing topics that are relevant to practicing teachers.…

  10. Determination of auroral heat fluxes and thermal ion outflows using a numerical ionospheric model and incoherent-scatter radar data

    SciTech Connect

    Min, Q.L.; Watkins, B.J.

    1995-01-01

    A comprehensive one-dimensional model of the polar ionosphere has been used in conjunction with incoherent-scatter radar data from Sondrestrom, Greenland, to determine downward heat fluxes and thermal ion outflows at very high latitudes. For periods of very quiet geomagnetic activity the model closely simulates the observed time-dependent behavior of the electron density, ion and electron temperatures. To obtain this similarity between model and data, the upper boundary conditions of the model, namely downward heat flux, and magnetic field-aligned ion flows, are continually adjusted with time to provide a best fit with data. The heat fluxes and ion flows are determined indirectly from this fitting procedure. The technique has been applied to a 10-hour daytime data set for February 12, 1990, to search for enhanced downward heat fluxes and outward thermal ion fluxes associated with dayside auroral oval. Variations of heat flux ranged from about 2 x 10{sup 9} to 2 x 10{sup 10} eVcm{sup {minus}2}s{sup {minus}1}, and vertical outward fluxes of ionization ranged from about zero to 8 x 10{sup 8} cm{sup {minus}2}s{sup {minus}1}. For both quantities the peak values occurred when the radar site was located under the dayside auroral oval. It is suggested that these marked upward thermal ion flows in the dayside auroral ionosphere may be associated with energetic O{sup +} ion outflows that have been observed at high altitudes with spacecraft. 12 refs., 6 figs.

  11. Impact of Model Uncertainties on Quantitative Analysis of FUV Auroral Images: Peak Production Height

    NASA Technical Reports Server (NTRS)

    Germany, G. A.; Lummerzheim, D.; Parks, G. K.; Brittnacher, M. J.; Spann, James F., Jr.; Richards, Phil G.

    1999-01-01

    We demonstrate that small uncertainties in the modeled height of peak production for FUV emissions can lead to significant uncertainties in the analysis of these sai-ne emissions. In particular, an uncertainty of only 3 km in the peak production height can lead to a 50% uncertainty in the mean auroral energy deduced from the images. This altitude uncertainty is comparable to differences in different auroral deposition models currently used for UVI analysis. Consequently, great care must be taken in quantitative photometric analysis and interpretation of FUV auroral images.

  12. Current-driven plasma instabilities and auroral-type particle acceleration at Venus

    NASA Technical Reports Server (NTRS)

    Scarf, F. L.; Brace, L. H.; Russell, C. T.; Luhmann, J. G.; Stewart, A. I. F.

    1985-01-01

    Above the ionosphere of Venus, several instruments on the Pioneer Orbiter detect correlated wave, field and particle phenomena suggestive of current-driven anomalous resistivity and auroral-type particle acceleration. In localized regions the plasma wave instrument measures intense mid-frequency turbulence levels together with strong field-aligned currents. Here the local parameters indicate that there is marginal stability for ion acoustic waves, and the electron temperature probe finds evidence that energetic primaries are present. This suggests an auroral-type energy deposition into the upper atmosphere of Venus. These results appear to be consistent with the direct measurements of auroral emissions from the Pioneer-Venus ultraviolet imaging spectrometer.

  13. Auroral-particle precipitation and trapping caused by electrostatic double layers in the ionosphere.

    PubMed

    Albert, R D; Lindstrom, P J

    1970-12-25

    Interpretation of high-resolution angular distribution measurements of the primary auroral electron flux detected by a rocket probe launched into a visible aurora from Fort Churchill in the fall of 1966 leads to the following conclusions. The auroral electron flux is nearly monoenergetic and has a quasi-trapped as well as a precipitating component. The quasi-trapped flux appears to be limited to a region defined by magnetic-mirror points and multiple electrostatic double layers in the ionosphere. The electrostatic field of the double-layer distribution enhances the aurora by lowering the magnetic-mirror points and supplying energy to the primary auroral electrons.

  14. The amplitude of auroral backscatter. I - Model estimates of the dependence on electron density

    NASA Astrophysics Data System (ADS)

    Uspenskii, M. V.; Williams, P. J. S.

    1988-01-01

    A model of the auroral backscatter amplitude, in the form discussed by Uspensky (1985) and Oksman et al. (1986), has been derived for the radar geometry appropriate to joint observations by the PGI auroral radars at Karmaselga and Essoyla and the EISCAT incoherent scatter radar. The model shows how refraction effects cause a strongly nonlinear dependence of backscatter amplitude on electron density in the E-region. It also explains why the macroaspect sensitivity for auroral radar operating at a frequency of about 45 MHz is only 1-2 dB per degree for aspect angles greater than 5 deg.

  15. The aurora as a source of planetary-scale waves in the middle atmosphere. [atmospheric turbulence caused by auroral energy absorption

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.; Straus, J. M.

    1974-01-01

    Photographs of global scale auroral forms taken by scanning radiometers onboard weather satellites in 1972 show that auroral bands exhibit well organized wave motion with typical zonal wave number of 5 or so. The scale size of these waves is in agreement with that of well organized neutral wind fields in the 150- to 200-km region during the geomagnetic storm of May 27, 1967. Further, the horizontal scale size revealed by these observations are in agreement with that of high altitude traveling ionospheric disturbances. It is conjectured that the geomagnetic storm is a source of planetary and synoptic scale neutral atmospheric waves in the middle atmosphere. Although there is, at present, no observation of substorm related waves of this scale size at mesospheric and stratospheric altitudes, the possible existence of a new source of waves of the proper scale size to trigger instabilities in middle atmospheric circulation systems may be significant in the study of lower atmospheric response to geomagnetic activity.

  16. Commercial Style Market Research for Navy Activities

    DTIC Science & Technology

    1993-12-01

    market research and analysis and indicate their impact on the various elements of the plan. If the acquisition or part...was not or will not be conducted.. .Once the Government’s needs have been func- tionally described, market research and analysis shall be conducted to...Systems Management College, 1993, pp. 409-420. 44. Lee, Christopher, Office Director, Office of Market Research and Analysis , Defense Fuels Supply

  17. Biology Research Activities: Teacher's Edition (with Answers).

    ERIC Educational Resources Information Center

    Newman, Barbara

    This book is part of the series "Explorations in Science" which contains enrichment activities for the general science curriculum. Each book in the series contains innovative and traditional projects for both the bright and average, the self-motivated, and those who find activity motivating. Each activity is self-contained and provides everything…

  18. Fitness and Physical Activity. Research Brief

    ERIC Educational Resources Information Center

    Walker, Karen

    2005-01-01

    What can be done to support fitness and physical activity? Schools can guide students in developing life-long habits of participating in physical activities. According to the National Association for Sports and Physical Education, the concepts of physical fitness activities and physical education are used synonymously, however, they are not the…

  19. Sources of field-aligned currents in the auroral plasma

    SciTech Connect

    Marshall, J.A.; Burch, J.L. ); Kan, J.R. ); Reiff, P.H. ); Slavin, J.A. )

    1991-01-01

    Data from the Dynamics Explorer 1 High Altitude Plasma Instrument (HAPI) and magnetometer are used to investigate the sources of field-aligned currents in the nightside auroral zone. It is found that the formula developed by S. Knight predicts the field-aligned current density fairly accurately in regions where a significant potential drop can be inferred from the HAPI data; there are, however, regions in which the proportionality between potential drop and field-aligned current does not hold. In particular, the authors note occurrences of strong upward field-aligned current associated not with inverted-V events but instead with suprathermal bursts. In addition, upward field-aligned currents are often observed to peak near the edges of inverted-V events, rather than in the center as would be predicted by Knight.

  20. Sources of field-aligned currents in the auroral plasma

    NASA Astrophysics Data System (ADS)

    Marshall, J. A.; Burch, J. L.; Kan, J. R.; Reiff, P. H.; Slavin, J. A.

    1991-01-01

    Data from the Dynamics Explorer 1 High Altitude Plasma Instrument (HAPI) and magnetometer are used to investigate the sources of field-aligned currents in the nightside auroral zone. It is found that the formula developed by S. Knight predicts the field-aligned current density fairly accurately in regions where a significant potential drop can be inferred from the HAPI data; there are, however, regions in which the proportionality between potential drop and field-aligned current does not hold. In particular, occurrences of strong upward field-aligned current associated not with inverted-V events but instead with suprathermal bursts are noted. In addition, upward field-aligned currents are often observed to peak near the edges of inverted-V events, rather than in the center as would be predicted by Knight.

  1. Theory of auroral zone PiB pulsation spectra

    SciTech Connect

    Lysak, R.L. )

    1988-06-01

    Changes in the auroral zone current system are often accompanied by magnetic pulsations with periods of about 1 s. These so-called bursts of irregular pulsations (PiB) have been observed both on ground magnetograms and with in situ satellite observations. These pulsations can be understood as excitations of a resonant cavity in the topside ionosphere, where the Alfven speed has a strong gradient due to the exponential decrease of density above the ionosphere. These waves have a frequency which scales as the ratio of the Alfven speed at the ionosphere divided by the ionospheric scale height. For a pure exponential Alfven speed profile, the mode frequencies are related to zeros of the zeroth-order Bessel function. For other profiles of the density, and therefore Alfven speed, the frequencies are not exactly given by the simple theory, but the frequency and mode structure are similar provided the Alfven speed sharply increases above the ionosphere.

  2. The Origin and Shape of Diffuse Auroral Patches

    NASA Technical Reports Server (NTRS)

    Rae, Kyle; Donovan, Eric; Liang, Jun; Spanswick, Emma L.; Lessard, Marc; Jones, Sarah; Jaynes, Allison N.

    2011-01-01

    Patchy pulsating aurora occurs commonly in the post-midnight sector. Recent studies have moved us significantly closer to understanding the mechanisms responsible for pitch angle scattering of the Central Plasma Sheet (CPS) electrons that produce these aurora. However, there is not yet an adequate explanation of what physical process gives rise to the patchy nature of the aurora. These patches last for minutes up to tens of minutes, with sizes that do not change significantly over their life time, and remain more or less stationary relative to the ground. In this paper, we use THEMIS and NORSTAR ASI observations of these auroral features to explore the shape of these patches. Based on our results, we conclude that the patches are the ionospheric counterpart of structures in cold plasma near the magnetospheric equator.

  3. Auroral kilometric radiation source region observations from ISIS 1

    NASA Technical Reports Server (NTRS)

    Benson, R. F.

    1981-01-01

    The ISIS 1 observations of the high-frequency portion of the auroral kilometric radiation (AKR) spectrum are considered, that is, from the minimum frequency encountered for the extraordinary mode cut-off (approximately 450 kHz) to the upper frequency cut-off (approximately 800 kHz). AKR is found to be generated in the extraordinary mode just above the local cutoff frequency and to emanate in a direction that is nearly perpendicular to the magnetic field. It occurs within local depletions of electron density, where the ratio of plasma frequency to cyclotron frequency is below 0.2. The density depletion is restricted to altitudes above approximately 2,000 km, and the upper AKR frequency limit corresponds to the extraordinary cutoff frequency at this altitude.

  4. Electron angular distributions above the dayside auroral oval

    NASA Technical Reports Server (NTRS)

    Craven, J. D.; Frank, L. A.

    1975-01-01

    An electrostatic analyzer was employed on the Ariel 4 satellite to determine pitch angle distributions of electron intensities over the dayside auroral oval. Two major precipitation zones were encountered: an equatorward zone of broad spectra with intensities of approximately 1000 electrons/(sq cm-sec-sr-eV) and a poleward zone, the polar cusp, with intensities typical of those of the magnetosheath. Angular distributions within the equatorward zone are generally isotropic outside of the atmospheric backscatter cone. The precipitation mechanism appears to be pitch angle scattering near the distant magnetic equator. In contrast, pitch angle distributions within the polar cusp are often found to be strongly field aligned with intensities within the atmospheric loss cone greater by factors of approximately 10 than the mirroring intensities. These distributions are qualititatively similar to those for the inverted V precipitation events at later local times, and probably share a common acceleration mechanism with the inverted V phenomenon.

  5. A stable auroral red (SAR) arc with multiple emission features

    NASA Astrophysics Data System (ADS)

    Mendillo, Michael; Finan, Robert; Baumgardner, Jeffrey; Wroten, Joei; Martinis, Carlos; Casillas, Marcus

    2016-10-01

    Stable auroral red (SAR) arcs offer subvisible evidence for storm time linkages between the inner magnetosphere and the midlatitude ionosphere. A SAR arc's defining characteristics are horizon-to-horizon east-west extent, a few degrees of latitude in meridional extent, emission only at the oxygen 6300Å line, and minimal brightness changes during a night—effects readily provided by steady heat conduction from the ring current-plasmapause interaction region. Here we describe a typical SAR arc (brightness 300 rayleighs) with several superimposed patches of emission in two oxygen lines (with a 6300Å/5577Å ratio of 40). We find no evidence for highly localized heating effects but rather evidence from GPS satellites supporting low-energy electron precipitation as the SAR arc modulating mechanism. Seven brightness peaks with average longitude spacing of 4° define a new spatial pattern for SAR arc studies.

  6. Solar Array and Auroral Charging Studies of DMSP Spacecraft

    NASA Technical Reports Server (NTRS)

    Matias, Kelwin

    2013-01-01

    The SSJ electrostatic analyzers and the SSIES plasma instruments on the DMSP spacecraft in low Earth polar orbit can be used to conduct case studies of auroral and solar array charging. We will use a program written in the Interactive Data Language (IDL) to evaluate questionable charging events in the SSJ records by comparing charging signatures in SSJ and SSIES data. In addition, we will assemble a number of case studies of solar array charging showing the signatures from the SSJ data and compare them to the SSIES charging signatures. In addition, we will use Satellite Tool Kit (STK) to propagate orbits, obtain solar intensity, and use to verify onset of charging with sunrise.

  7. Characteristics of a stable auroral red arc event

    NASA Technical Reports Server (NTRS)

    Kozyra, J. U.; Cravens, T. E.; Nagy, A. F.; Chandler, M. O.; Brace, L. H.; Maynard, N. C.; Slater, D. W.; Emery, B. A.; Shawhan, S. D.

    1982-01-01

    The present investigation is concerned with an analysis of the measurements of the stable auroral red (SAR) arc of October 23, 1981, using data from orbit 1192 of Dynamics Explorer (DE) 2, during which a magnetic coincidence occurred with the DE-1 spacecraft near the red arc field line, and for which simultaneous ground-based intensity measurements from Richland, WA were available. The altitude of the DE-2 satellite was approximately 850 km during arc passage in the Northern Hemisphere and approximately 395 km during the conjugate hemisphere passage. The DE-1 satellite was at an altitude of approximately 6000 km during the magnetic coincidence with DE-2 in the Northern Hemisphere. The described observations and calculations reconfirm a previous understanding that the actual excitation of the O(1D) state responsible for the 6300 A emission of red arcs is caused by hot ionospheric thermal electrons.

  8. Transverse Acceleration of Ions in the Auroral Ionosphere

    NASA Astrophysics Data System (ADS)

    Ram, A. K.; Benisti, D.; Bers, A.

    1996-11-01

    We show that the recent observations of transverse acceleration of O^+ and H^+ ions in localized regions of the auroral ionosphere,(J. L. Vago et. al., J. Geophys. Res.), 97, 16935 (1992). where intense lower-hybrid waves exist, can be understood in terms of the nonlinear interaction of ions with electrostatic wave packets of finite bandwidth in frequency and wavelength. Contrary to previous studies, we find that motion of the ions does not need to become chaotic in order to explain the observed energies needed to escape the ionosphere. The energization process of thermal ions is coherent and occurs over times that are long compared to the ion gyration times. This coherent energization occurs when the ions interact with more than a single plane wave of differing frequencies. The conditions for the energization and an explanation of the observations will be discussed.

  9. OEDIPUS-C Topside Sounding of an Auroral E Region

    NASA Astrophysics Data System (ADS)

    Prikryl, P.; James, H. G.; Knudsen, D. J.

    1999-01-01

    The OEDIPUS-C rocket payload included a bistatic tethered HF instrument transmitter-receiver pair HEX-REX (High Frequency Exciter - Receiver for Exciter) which acted as a topside sounder. The relatively low altitudes through which OEDIPUS C carried out topside sounding make the resulting ionograms a novel data set. Ionospheric reflections of the 10-W HEX transmissions were detected at payload heights between 780 and 160 km on the down leg. Near apogee at 824 km, extremely low in-situ densities (~100 cm-3) were observed. The monotonic rise of density from apogee to re-entry clearly showed that there was no ionospheric F layer. The ionospheric echoes came from altitudes near the payload down to ~100 km. Ground-reflection traces were often seen at frequencies below both fOE and fxE. OEDIPUS C provided a close-hand view of a thick but porous auroral E layer sounded at small ranges

  10. Tethered two-point measurements of solitary auroral density cavities

    NASA Astrophysics Data System (ADS)

    Knudsen, D. J.; Wallis, D. D.; James, H. G.

    The OEDIPUS-C sounding rocket observed localized plasma density depletions in the topside auroral ionosphere using two Langmuir probes situated on separate subpayloads several hundred meters apart. One probe was biased in electron saturation (+5 V) and the second in ion saturation (-5 V). Both of these measurements are consistent with density depletions of tens of percent. The depletions have cross-field dimensions of tens of meters and occur in regions of VLF hiss, suggesting they are likely signatures of lower hybrid solitary structures. Time delays between event detections on the two subpayloads are consistent with spatially localized structures traversed in succession. The two-point measurements show directly that the cavities extend at least 800 m along the geomagnetic field line, and the apparent electric potential within them is depressed by roughly 0.5 V.

  11. Nursing research--taking an active interest.

    PubMed

    Cleverly, D

    1998-05-01

    This paper discusses the issues raised by the still unfolding transformation of nurse education attitudes to research, from the traditional stance--that it was something that other people do--to the realization that quality research is central to the development of the profession and its competitive survival into the 21st century. In particular, the problems and challenges presented by the Higher Education Funding Council for England research assessment exercise, and the policy of the funding council, are examined. Research in schools of nursing is reviewed under the headings of funding, contracts, support, discipline, publication and staff recruitment and retention, to attempt to identify those approaches most likely to yield a research output of an acceptable volume and quality.

  12. Auroral spectral estimation with wide-band color mosaic CCDs

    NASA Astrophysics Data System (ADS)

    Jackel, B. J.; Unick, C.; Syrjäsuo, M. T.; Partamies, N.; Wild, J. A.; Woodfield, E. E.; McWhirter, I.; Kendall, E.; Spanswick, E.

    2014-06-01

    Optical aurora can be structured over a wide range of spatial and temporal scales with spectral features that depend on the energy of precipitating particles. Scientific studies typically combine data from multiple instruments that are individually optimized for spatial, spectral, or temporal resolution. One recent addition combines all-sky optics with color mosaic CCD (charge-coupled device) detectors that use a matrix of different wide-band micro-filters to produce an image with several (often three) color channels. These devices provide sequences of two dimensional multispectral luminosity with simultaneous exposure of all color channels allowing interchannel comparison even during periods with rapidly varying aurora. At present color auroral image data are primarily used for qualitative analysis. In this study a quantitative approach based on Backus-Gilbert linear inversion was used to better understand the effective spectral resolution of existing and proposed instruments. Two spectrally calibrated commercial detectors (Sony ICX285AQ and ICX429AKL) with very different color mosaics (RGB (red, green, blue) vs. CYGM (cyan, yellow, green, magenta)) were found to have very similar spectral resolution: three channels with FWHM (full-width half-maximum) ≈100 nm; a NIR (near infrared) blocking filter is important for stabilizing inversion of both three-channel configurations. Operating the ICX429AKL in a noninterlaced mode would improve spectral resolution and provide an additional near infrared channel. Transformations from arbitrary device channels to RGB are easily obtained through inversion. Simultaneous imaging of multiple auroral emissions may be achieved using a single-color camera with a triple-pass filter. Combinations of multiple cameras with simple filters should provide ~50 nm resolution across most of the visible spectrum. Performance of other instrument designs could be explored and compared using the same quantitative framework.

  13. Statistical properties of substorm auroral onset beads/rays

    NASA Astrophysics Data System (ADS)

    Nishimura, Y.; Yang, J.; Pritchett, P. L.; Coroniti, F. V.; Donovan, E. F.; Lyons, L. R.; Wolf, R. A.; Angelopoulos, V.; Mende, S. B.

    2016-09-01

    Auroral substorms are often associated with optical ray or bead structures during initial brightening (substorm auroral onset waves). Occurrence probabilities and properties of substorm onset waves have been characterized using 112 substorm events identified in Time History of Events and Macroscale Interactions during Substorms (THEMIS) all-sky imager data and compared to Rice Convection Model-Equilibrium (RCM-E) and kinetic instability properties. All substorm onsets were found to be associated with optical waves, and thus, optical waves are a common feature of substorm onset. Eastward propagating wave events are more frequent than westward propagating wave events and tend to occur during lower-latitude substorms (stronger solar wind driving). The wave propagation directions are organized by orientation of initial brightening arcs. We also identified notable differences in wave propagation speed, wavelength (wave number), period, and duration between westward and eastward propagating waves. In contrast, the wave growth rate does not depend on the propagation direction or substorm strength but is inversely proportional to the wave duration. This suggests that the waves evolve to poleward expansion at a certain intensity threshold and that the wave properties do not directly relate to substorm strengths. However, waves are still important for mediating the transition between the substorm growth phase and poleward expansion. The relation to arc orientation can be explained by magnetotail structures in the RCM-E, indicating that substorm onset location relative to the pressure peak determines the wave propagation direction. The measured wave properties agree well with kinetic ballooning interchange instability, while cross-field current instability and electromagnetic ion cyclotron instability give much larger propagation speed and smaller wave period.

  14. Inverse electron energy dispersion from moving auroral forms

    NASA Astrophysics Data System (ADS)

    Cameron, Taylor; Knudsen, David

    2016-12-01

    Numerous published examples of energy-dispersed bursts show electron energies reaching as high as several keV and decaying to lower energies over a fraction of 1 s. This signature has been interpreted by some authors as due to impulsive acceleration to a broad range of energies in a localized region and by others as the result of impulsive, dispersive Alfvén waves, in which case the acceleration takes place over an extended distance along magnetic field lines. A survey by the Suprathermal (0-350 eV) Electron Imager on the Enhanced Polar Outflow Probe (ePOP) in the topside ionosphere has produced examples of high-to-low ("regular") energy dispersion, but also a smaller number of examples exhibiting low-to-high ("inverse") dispersion, which to our knowledge has not been reported before. Motivated by a recent report of regular electron dispersion produced by auroral rays moving faster than the E × B drift speed, we investigate a heuristic model of electron acceleration within a region of uniform electric field parallel to B which extends a distance La along magnetic field lines. We show that in addition to a broad range of energies, this model produces inverse dispersion when the detector is less than La beneath the bottom of the acceleration region and regular dispersion for detector distances larger than La. This simple model is meant to inform future efforts to construct a more physical model of suprathermal electron acceleration within moving auroral forms and suggests that inverse dispersion indicates relative proximity to an altitude-extended acceleration region.

  15. Unambiguous evidence of HF pump-enhanced airglow at auroral latitudes

    NASA Astrophysics Data System (ADS)

    Brändström, B. U. E.; Leyser, T. B.; Steen, Å.; Rietveld, M. T.; Gustavsson, B.; Aso, T.; Ejiri, M.

    1999-12-01

    Simultaneous observations by up to three low-light imaging stations belonging to the Auroral Large Imaging System (ALIS) have provided the first strong evidence of high-frequency (HF) pump-enhanced airglow at auroral latitudes. The airglow was enhanced by an ordinary mode 4.04 MHz electromagnetic wave with an effective radiated power (ERP) of about 210 MW that was transmitted from the EISCAT-Heating facility near Tromsø, Norway. While often observed at low or mid-latitudes, and despite numerous earlier experiments, no unambiguous observations of pump-enhanced airglow have been reported at auroral latitudes. On February 16, 1999, the first successful results were obtained, and this paper concentrates on discussing optical data from this event. Triangulated estimations of the altitude and position of the enhanced airglow are also presented. Auroral-latitude observations of HF pump-enhanced airglow are important in order to better understand the underlying excitation mechanisms.

  16. Relationship between Alfvén Wave and Quasi-Static Acceleration in Earth's Auroral Zone

    NASA Astrophysics Data System (ADS)

    Mottez, Fabrice

    2016-02-01

    There are two main categories of acceleration processes in the Earth's auroral zone: those based on quasi-static structures, and those based on Alfvén wave (AW). AWs play a nonnegligible role in the global energy budget of the plasma surrounding the Earth because they participate in auroral acceleration, and because auroral acceleration conveys a large portion of the energy flux across the magnetosphere. Acceleration events by double layers (DLs) and by AW have mostly been investigated separately, but many studies cited in this chapter show that they are not independent: these processes can occur simultaneously, and one process can be the cause of the other. The quasi-simultaneous occurrences of acceleration by AW and by quasi-static structures have been observed predominantly at the polar cap boundary of auroral arc systems, where often new bright arcs develop or intensify.

  17. Auroral vector electric field and particle comparisons. II - Electrodynamics of an arc

    NASA Technical Reports Server (NTRS)

    Evans, D. S.; Maynard, N. C.; Troim, J.; Jacobsen, T.; Egeland, A.

    1977-01-01

    The paper reports the results of energetic auroral electron and vector electric field measurements taken near and above a discrete auroral form and discusses their electrodynamic implications. Height-integrated Hall and Pedersen conductivities are computed in a quantitative fashion along the rocket payload trajectory. These conductivities, together with the electric fields, are used to describe the local auroral electrojet current system and to demonstrate an inverse relationship between the local electric field intensity and the height-integrated Pedersen conductivity. An analysis is presented of the divergence of both the electric field and the horizontal current as an effort to infer space charge densities and magnetic-field-aligned electrical currents near an auroral arc.

  18. Modulation of auroral electrojet currents using dual modulated HF beams with ELF phase offset, a potential D-region ionospheric diagnostic

    NASA Astrophysics Data System (ADS)

    GołKowski, M.; Cohen, M. B.; Moore, R. C.

    2013-05-01

    Experiments at the ionospheric heating facility of the High Frequency Active Auroral Research Program (HAARP) are performed employing dual HF beams amplitude modulated at ELF/VLF with a phase offset between the two modulation waveforms. The amplitude of the observed ELF/VLF waves is strongly dependent on the imposed ELF/VLF phase offset, the modulation waveform, and the orientation of the HF beams. Data from two ground stations are interpreted using simulations of modulated heating power envelopes as well as a comprehensive model of ionospheric ELF/VLF generation. It is found that two colocated vertical beams HF beams excite a single ionospheric ELF/VLF source, but independent ELF/VLF sources can be induced in the ionospheric region above the heater if the HF beams are offset from zenith to intersect at their 3 dB points. Furthermore, the use of two vertical HF beams with ELF phase offset is found to be a potential diagnostic method for the ionospheric D region.

  19. Research in subliminal psychodynamic activation: note on Masling (1998).

    PubMed

    Fudin, R

    1999-04-01

    Masling (1998) questioned Malik, Apel, Nelham, Rutkowski, and Ladd's 1997 suggestion that subliminal psychodynamic activation research with MOMMY AND I ARE ONE should be restricted. Problems in Masling's paper and the scope of research with MOMMY AND I ARE ONE are discussed. His position that such research should not be restricted is supported on the condition that subliminal psychodynamic activation research with MOMMY AND I ARE ONE (and other messages) use Fudin's 1986 procedure that could clarify the interpretation of successful experimental outcomes.

  20. Local increases in auroral electron precipitation which were not accompanied by a corresponding increase in the electric potential of the auroral electron acceleration region

    NASA Astrophysics Data System (ADS)

    Calvert, W.; Hardy, D. A.

    The Oedipus C rocket that was launched from Poker Flats, Alaska in November 1995 has detected significant local increases in the observed auroral electron precipitation flux during an auroral substorm which were not accompanied by a corresponding increase in the electric potential of the auroral electron acceleration region. The energy of the electrons which contributed to these increases in flux were also found to extend well below the electric potential energy of these electrons at the top of the acceleration region, thereby requiring a related loss in energy inside the acceleration region. This loss in energy must therefore be attributed to a wave instability which extracts energy from the electrons which are scattered into the loss cone inside the electron acceleration region to cause the discrete aurora during a substorm.

  1. Features of Pc5 pulsations in the geomagnetic field, auroral luminosity, and Riometer absorption

    NASA Astrophysics Data System (ADS)

    Belakhovsky, V. B.; Pilipenko, V. A.; Samsonov, S. N.; Lorentsen, D.

    2016-01-01

    Simultaneous morning Pc5 pulsations ( f ~ 3-5 mHz) in the geomagnetic field, aurora intensities (in the 557.7 and 630.0 nm oxygen emissions and the 471.0 nm nitrogen emission), and riometer absorption, were studied based on the CARISMA, CANMOS, and NORSTAR network data for the event of January 1, 2000. According to the GOES-8 satellite observations, these Pc5 geomagnetic pulsations are observed as incompressible Alfvén waves with toroidal polarization in the magnetosphere. Although the Pc5 pulsation frequencies in auroras, the geomagnetic field, and riometer absorption are close to one another, stable phase relationships are not observed between them. Far from all trains of geomagnetic Pc5 pulsations are accompanied by corresponding auroral pulsations; consequently, geomagnetic pulsations are primary with respect to auroral pulsations. Both geomagnetic and auroral pulsations propagate poleward, and the frequency decreases with increasing geomagnetic latitude. When auroral Pc5 pulsations appear, the ratio of the 557.7/630.0 nm emission intensity sharply increases, which indicates that auroral pulsations result from not simply modulated particle precipitation but also an additional periodic acceleration of auroral electrons by the wave field. A high correlation is not observed between Pc5 pulsations in auroras and the riometer absorption, which indicates that these pulsations have a common source but different generation mechanisms. Auroral luminosity modulation is supposedly related to the interaction between Alfvén waves and the region with the field-aligned potential drop above the auroral ionosphere, and riometer absorption modulation is caused by the scattering of energetic electrons by VLF noise pulsations.

  2. Initial results from the operation of two argon ion generators in the auroral ionosphere

    NASA Technical Reports Server (NTRS)

    Erlandson, R. E.; Cahill, L. J., Jr.; Pollock, C. J.; Arnoldy, R. L.; Scales, W. A.

    1987-01-01

    Two argon ion generators have been lofted by sounding rockets in order to investigate ion beam dynamics and beam effects on the ionosphere, and auroral electrodynamics during rocket passage over auroral arcs. The ion generators were on a subpayload that was separated from the main payload early in the flight. The main payload conducted the diagnostic measurements during ion beam operations. Evidence of heating of the ionosphere around the subpayload during each ion beam emission is noted.

  3. Dependence of poleward auroral and equatorward motion on substorm current wedge

    NASA Astrophysics Data System (ADS)

    Chu, X.; McPherron, R. L.; Hsu, T. S.; Angelopoulos, V.; Pu, Z.; Yao, Z.; Zhang, H.; Connors, M. G.

    2014-12-01

    Flux pileup from fast flows and dipolarization, physical processes in the magnetotail, cause auroral evolution (brightening, poleward expansion, and equatorward motion) in the ionosphere during substorms. Although such flows have been shown to produce auroral brightening, the causes of auroral poleward expansion and equatorward motion remain unclear. Two mechanisms, tailward movement of the pileup region and dipolarization of the substorm current wedge (SCW), are thought to contribute to auroral poleward expansion, but no study has addressed which mechanism makes the dominant contribution. The hypothesis that auroral poleward expansion is caused by the tailward-moving pileup region is based on the assumption of a steady magnetosphere. This assumption is not necessarily true during substorms, however, because dipolarization of the SCW changes magnetospheric configuration and thus ionospheric footprints (and mapping) of the flows. Because they lack a dynamic SCW, previous magnetospheric models are statistical and static. We evaluated the dynamic effect of the SCW using a dynamic magnetospheric model in which the SCW is superimposed on Tsyganenko model. The current wedge is obtained from a recently developed inversion model using only ground magnetic field data as input, and model parameters are updated every minute. Applying our dynamic magnetospheric model to data from an isolated substorm observed by THEMIS and GOES 10 spacecraft and ground ASIs on 13 February 2008, we found that 1) our model predicts dipolarization at GOES 10 (it can predict near-Earth magnetic variations with ground data alone); 2) there is a good temporal correlation between successive auroral brightenings and flows; 3) flow footprints from our model are collocated with auroral poleward expansion and equatorward motion. These results suggest that in this event, auroral poleward expansion and equatorward motion are mainly caused by mapping changes in the dynamic magnetosphere by the SCW.

  4. HST/STIS observation of Ganymede's aurora: Investigating the variability of the auroral ovals

    NASA Astrophysics Data System (ADS)

    Musacchio, Fabrizio; Saur, Joachim; Roth, Lorenz; Duling, Stefan; Feldman, Paul D.; Strobel, Darrell F.; Retherford, Kurt D.; McGrath, Melissa A.

    2014-05-01

    We analyze the variability of Ganymede's FUV auroral ovals using spectral images acquired during two visits in 2010 and 2011 with Hubble's Space Telescope Imaging Spectrograph (HST/STIS) when Ganymede was at eastern elongation. The observed electron-impact-excited auroral emissions from Ganymede's O2 atmosphere are thought to be driven by electron acceleration by strong field-aligned currents at the separatrix, i.e., at the boundary area between open and closed magnetic field lines of Ganymede's mini-magnetosphere. The location of the auroral ovals correlates with the intersection of this separatrix and the satellite's surface and therefore strongly depends on the interaction between Ganymede's magnetic field and atmosphere with the local time-variable plasma environment. In our study we particularly analyze the latitudinal positions of the auroral ovals in order to better understand the correlation with the plasma environment. The HST campaign was designed such that the full range of Ganymede's magnetic-latitudinal positions within Jupiter's current sheet is covered. We provide a mapping of auroral emission distribution and study the auroral brightness as a function of Ganymede's position in Jupiter's magnetosphere.

  5. Correspondence between the ULF wave power spatial distribution and auroral oval boundaries

    NASA Astrophysics Data System (ADS)

    Kozyreva, Olga; Pilipenko, Vyacheslav; Engebretson, Mark; Klimushkin, Dmitriy; Mager, Pavel

    2016-06-01

    The world-wide spatial distribution of the wave power in the Pc5 band during magnetic storms has been compared with auroral oval boundaries. The poleward and equatorward auroral oval boundaries are estimated using either the British Antarctic Survey database containing IMAGE satellite UV observations of the aurora or the OVATION model based on the DMSP particle data. The "epicenter" of the spectral power of broadband Pc5 fluctuations during the storm growth phase is mapped inside the auroral oval. During the storm recovery phase, the spectral power of narrowband Pc5 waves, both in the dawn and dusk sectors, is mapped inside the auroral oval or around its equatorward boundary. This observational result confirms previously reported effects: the spatial/temporal variations of the Pc5 wave power in the morning/pre-noon sector are closely related to the dynamics of the auroral electrojet and magnetospheric field-aligned currents. At the same time, narrowband Pc5 waves demonstrate typical resonant features in the amplitude-phase latitudinal structure. Thus, the location of the auroral oval or its equatorward boundary is the preferred latitude for magnetospheric field-line Alfven resonator excitation. This effect is not taken into account by modern theories of ULF Pc5 waves, but it could be significant for the development of more adequate models.

  6. Enhanced MUF propagation of HF radio waves in the auroral zone

    NASA Astrophysics Data System (ADS)

    Milan, S. E.; Jones, T. B.; Warrington, E. M.

    1997-01-01

    Four high frequency propagation paths were monitored from a transmitter located within the polar cap by four receivers located variously within the polar cap and at sub-auroral latitudes. Of these paths, one was contained entirely within the polar cap at all times, two were trans-auroral at all times, and one varied from trans-auroral during the day to polar cap during the night. Fourteen frequencies within the HF band were transmitted each hour for the duration of two 24 day experimental campaigns during the summer of 1988 and the winter of 1989. From an analysis of the received signals the confidence of signal recognition and signal strength were determined. During geomagnetically undisturbed periods the propagation behaviour resembled that of mid-latitude paths. During geomagnetically disturbed times, however, night-time propagation occurred on frequencies up to and sometimes over 10 MHz above the undisturbed night-time MUF, for periods of 2 to 6 h. These features appeared on the trans-auroral paths only and were attributed to E region (and occasionally F region) enhancement by auroral precipitation. APEs (auroral E propagation events) occurred on over 50% of nights. The occurrence of APEs also coincided with ionospheric storm periods when the HF band available for propagation was otherwise significantly narrowed due to a depletion of the F region electron density.

  7. Magnetotail flux accumulation leading to auroral expansion and a substorm current wedge: case study

    NASA Astrophysics Data System (ADS)

    Chu, X.; McPherron, R. L.; Hsu, T. S.; Angelopoulos, V.; Weygand, J. M.; Strangeway, R. J.; Liu, J.

    2015-12-01

    Magnetotail burst busty flows, magnetic field dipolarization, and auroral poleward expansion are linked to the development of substorm current wedges (SCW). Although auroral brightening is often attributed to field-aligned currents (FACs) in the SCW produced by flow vorticity and pressure redistribution, in-situ observations addressing the mechanism that generates these currents have been scarce. Conjugate observations and modelling results utilizing magnetotail satellites, inversion technique for SCW, and auroral imagers were used to study the release, transport, and accumulation of magnetic flux by flows; dipolarization associated with substorm current wedge formation; and auroral poleward expansion during an isolated substorm on 13 February 2008. During early expansion phase, magnetic flux released by magnetic reconnection was transported by earthward flows. Some magnetic flux was accumulated in the near-Earth region, and the remainder was transported azimuthally by flow diversion. The accumulated flux created a high pressure region with vertically dipolarized and azimuthally bent magnetic field lines. The rotation of the magnetic field lines was consistent with the polarity of the SCW. In the near-Earth region, good agreement was found among the magnetic flux transported by the flows, the accumulated flux causing dipolarization inside the SCW, and the flux enclosed within the poleward-expanded auroral oval. This agreement demonstrates that magnetic flux from the flows accumulated and generated the SCW, the magnetic dipolarization, and the auroral poleward expansion. The quantity of accumulated flux appears to determine the amplitudes of these phenomena.

  8. Cassini Observations of Saturn's Nightside UV Auroral Oval: In Situ Evidence of its Periodic Motion

    NASA Astrophysics Data System (ADS)

    Bunce, E. J.; Grodent, D. C.; Provan, G.; Jinks, S.; Cowley, S. W.; Andrews, D. J.; Arridge, C. S.; Badman, S. V.; Dougherty, M. K.; Kurth, W. S.; Mitchell, D. G.

    2012-12-01

    In recent years we have benefitted greatly from the first in-orbit multi-wavelength images of Saturn's polar atmosphere from the Cassini spacecraft. Specifically, images obtained from the UltraViolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft provide an excellent view of the planet's auroral emissions, which in turn give an account of the large-scale magnetosphere-ionosphere coupling and dynamics within the system. However, obtaining a simultaneous view of the auroral regions with measurements of the magnetic field and plasma populations at high-latitudes is more difficult to routinely achieve. Here we present an unusual example, during Revolution 99 in 2009, where UVIS images the entire northern UV auroral oval while Cassini traverses the magnetic flux tubes connecting to the auroral oval on the nightside sampling the related magnetic field and particle signatures present. We will discuss the relationship of the field-aligned currents (derived from the magnetic field), radio waves, and associated plasma electron and ion signatures to the properties of the auroral oval. The motion of the auroral oval evident in the UVIS images will be discussed in the context of the "planetary period oscillations" and previous field-aligned current studies.Credit: NASA/JPL/University of Colorado/ESA/University of Liege/University of Leicester

  9. Client satisfaction. Operations research activities and results.

    PubMed

    1998-06-01

    Operations research (OR) is a major component of the Quality Assurance Project's (QAP) strategy for improving the quality of health care delivery worldwide. QAP's Operations Research Program aims to improve the feasibility, utility, and cost-effectiveness of quality assurance strategies in developing countries. QAP and its field partners work to maximize the utility of each field study's findings. As such, the project hopes to disseminate information on all aspects of important OR projects, from the initial design to implementation and results. Over the course of the project, QAP's staff and their partners will develop studies in 16 technical areas. One key area of interest is the study of client satisfaction with health care delivery. The project currently has two major studies on client satisfaction underway in Niger and Peru. Phase one results from the Niger research and QAP and the Max Salud Institute in Peru are discussed.

  10. Boost-phase discrimination research activities

    NASA Technical Reports Server (NTRS)

    Cooper, David M.; Deiwert, George S.

    1989-01-01

    Theoretical research in two areas was performed. The aerothermodynamics research focused on the hard-body and rocket plume flows. Analytical real gas models to describe finite rate chemistry were developed and incorporated into the three-dimensional flow codes. New numerical algorithms capable of treating multi-species reacting gas equations and treating flows with large gradients were also developed. The computational chemistry research focused on the determination of spectral radiative intensity factors, transport properties and reaction rates. Ab initio solutions to the Schrodinger equation provided potential energy curves transition moments (radiative probabilities and strengths) and potential energy surfaces. These surfaces were then coupled with classical particle reactive trajectories to compute reaction cross-sections and rates.

  11. Comparison of very-low-frequency auroral hiss with precipitating low-energy electrons by the use of simultaneous data from two Ogo 4 experiments.

    NASA Technical Reports Server (NTRS)

    Hoffman, R. A.; Laaspere, T.

    1972-01-01

    Determination of the origin of auroral hiss by comparing the records of a vlf experiment (0.3 to 18 kHz) with simultaneous data obtained by an auroral-particle experiment having detectors for precipitating electrons at 0.7, 2.3, and 7.3 keV. It is found that, on the dayside of the earth, the occurrence of vlf hiss correlates well with precipitation events at 0.7 keV, but in general very poorly with activity in the higher-energy channels. Exact correlation between variations in vlf hiss intensity and in electron fluxes is rare even at 0.7 keV. In addition, vlf hiss tends to be observed over a somewhat larger spatial region than precipitating 0.7-keV electrons. It is concluded that, on the dayside, auroral hiss is generated by soft (E less than 1 keV) 'cusp region' electrons and that the lack of detailed correlation between the two phenomena is caused by propagation effects as the hiss travels downward and spreads from the generation region.

  12. Effects of magnetic-storm phases on F-layer irregularities from auroral to equatorial latitudes. Quarterly report, 1 Oct-31 Dec 91

    SciTech Connect

    Aarons, J.; Mendillo, M.

    1991-12-31

    Several periods of interest in the low sunspot years of 1985 and 1986 have been identified when data were available from Kiruna, Sweden and from Goose Bay, Labrador as well as from equatorial sites. A contouring program was developed to handle the Transit data and in fact have received data from several sample periods of very low magnetic activity over a period of several days. Just begun is this study of determining the pattern of F-layer irregularities during years of low solar flux. The evaluation of data sets has included new analysis (for Manila, for example) as well as evaluating older data, much of it at this date unused for scientific purposes. While F-region irregularities are frequently spoken of occuring in the auroral region, the behavior of the irregularities as a function of sunspot number is significantly different from the behavior of the auroral region. Auroral data, primarily of the E layer green line, show no significant changes as a function of sunspot number in the latitude of the occurrence of this phenomenon; F-region irregularities show a great movement towards the polar region with a low sunspot number. In order to predict the occurrence and level of the effects on trans-ionospheric propagation, the relationship to sunspot number must be ascertained. We feel the comparison of high latitude data from Sweden and Canada will allow us to state that a polar movement of the region during low sunspot years is a global phenomenon.

  13. Partnerships for progress in active living: from research to action

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The theme for the 2011 Active Living Research Annual Conference was "Partnerships for Progress in Active Living: From Research to Action." The rationale for this theme was simple: no person is an island. The theme recognizes that partnerships are essential to identify and implement solutions for co...

  14. Methods to Measure Physical Activity Behaviors in Health Education Research

    ERIC Educational Resources Information Center

    Fitzhugh, Eugene C.

    2015-01-01

    Regular physical activity (PA) is an important concept to measure in health education research. The health education researcher might need to measure physical activity because it is the primary measure of interest, or PA might be a confounding measure that needs to be controlled for in statistical analysis. The purpose of this commentary is to…

  15. Research activities of the Geodynamics Branch

    NASA Technical Reports Server (NTRS)

    Kahn, W. D. (Editor); Cohen, S. C. (Editor)

    1984-01-01

    A broad spectrum of geoscience disciplines including space geodesy, geopotential field modeling, tectonophysics, and dynamic oceanography are discussed. The NASA programs, include the Geodynamics and Ocean Programs, the Crustal Dynamics Project, the proposed Ocean Topography Experiment (TOPEX), and the Geopotential Research Mission (GRM). The papers are grouped into chapters on Crustal Movements, Global Earth Dynamics, Gravity Field Model Development, Sea Surface Topography, and Advanced Studies.

  16. Human Research Program Science Management: Overview of Research and Development Activities

    NASA Technical Reports Server (NTRS)

    Charles, John B.

    2007-01-01

    An overview of research and development activities of NASA's Human Research Science Management Program is presented. The topics include: 1) Human Research Program Goals; 2) Elements and Projects within HRP; 3) Development and Maintenance of Priorities; 4) Acquisition and Evaluation of Research and Technology Proposals; and 5) Annual Reviews

  17. A Typology of Nursing Research Activities According to Educational Preparation.

    ERIC Educational Resources Information Center

    Fawcett, Jacqueline

    1985-01-01

    A typology of research activities (generation of basic, applied, and clinical research; dissemination of findings; and use of findings) considered appropriate to nurses with different levels of educational preparation (ADN, BSN, MSN, DNSc/EdD, and PhD) is presented to assist potential researchers and nurse educators in undertaking realistic and…

  18. How consumer physical activity monitors could transform human physiology research.

    PubMed

    Wright, Stephen P; Hall Brown, Tyish S; Collier, Scott R; Sandberg, Kathryn

    2017-03-01

    A sedentary lifestyle and lack of physical activity are well-established risk factors for chronic disease and adverse health outcomes. Thus, there is enormous interest in measuring physical activity in biomedical research. Many consumer physical activity monitors, including Basis Health Tracker, BodyMedia Fit, DirectLife, Fitbit Flex, Fitbit One, Fitbit Zip, Garmin Vivofit, Jawbone UP, MisFit Shine, Nike FuelBand, Polar Loop, Withings Pulse O2, and others have accuracies similar to that of research-grade physical activity monitors for measuring steps. This review focuses on the unprecedented opportunities that consumer physical activity monitors offer for human physiology and pathophysiology research because of their ability to measure activity continuously under real-life conditions and because they are already widely used by consumers. We examine current and potential uses of consumer physical activity monitors as a measuring or monitoring device, or as an intervention in strategies to change behavior and predict health outcomes. The accuracy, reliability, reproducibility, and validity of consumer physical activity monitors are reviewed, as are limitations and challenges associated with using these devices in research. Other topics covered include how smartphone apps and platforms, such as the Apple ResearchKit, can be used in conjunction with consumer physical activity monitors for research. Lastly, the future of consumer physical activity monitors and related technology is considered: pattern recognition, integration of sleep monitors, and other biosensors in combination with new forms of information processing.

  19. NASA Glenn Research Center Battery Activities Overview

    NASA Technical Reports Server (NTRS)

    Manzo, Michelle A.

    2009-01-01

    This paper will provide an overview of the planned energy storage systems for the Orion Spacecraft and the Aries rockets that will be used in the return journey to the Moon and GRC's involvement in their development. Technology development goals and approaches to provide batteries and fuel cells for the Altair Lunar Lander, the new space suit under development for extravehicular activities (EVA) on the Lunar surface, and the Lunar Surface Systems operations will also be discussed.

  20. Corrosion Research And Web Site Activities

    NASA Technical Reports Server (NTRS)

    Heidersbach, Robert H.

    2001-01-01

    This report covers corrosion-related activities at the NASA Kennedy Space Center during the summer of 2000. The NASA Kennedy Space Center's corrosion web site, corrosion.ksc.nasa.gov, was updated with new information based on feedback over the past two years. The methodology for a two-year atmospheric exposure testing program to study the effectiveness of commercial chemicals sold for rinsing aircraft and other equipment was developed and some preliminary laboratory chemical analyses are presented.

  1. Corrosion Research and Web Site Activities

    NASA Technical Reports Server (NTRS)

    Heidersbach, Robert H.

    2002-01-01

    This report covers corrosion-related activities at the NASA Kennedy Space Center during the summer of 2000. The NASA Kennedy Space Center's corrosion web site, corrosion.ksc.nasa.gov, was updated with new information based on feedback over the past two years. The methodology for a two-year atmospheric exposure testing program to study the effectiveness of commercial chemicals sold for rinsing aircraft and other equipment was developed and some preliminary laboratory chemical analyses are presented.

  2. AUREOL-3 observations of new boundaries in the auroral ion precipitation

    NASA Technical Reports Server (NTRS)

    Bosqued, Jean M.; Ashour-Abdalla, Maha; El Alaoui, Mostafa; Zelenyj, Lev M.; Berthlier, Annick

    1993-01-01

    Interesting and well-separated structures in the 1-20 keV ion precipitation pattern have been revealed by an analysis of more than 50 crossings of the nightside (21-03 MLT) auroral zone by the AUREOL-3 satellite. First, velocity-dispersed ion structures (VDIS) are crossed near the poleward edge of the oval, and are the best ionospheric signature of ion beams flowing along the plasma sheet boundary layer. Proceeding equatorward, a large majority of VDIS events are bounded by a new and interesting narrow band of strongly reduced precipitation, or a gap, which delineates VDIS from the diffuse precipitation region connected to the CPS. A statistical analysis shows that the gap has an extent of about 1-2 deg, which is almost independent of magnetic activity; its location, about 70 deg ILAT, shifts significantly equatorward with higher magnetic activity levels. Intense electron arcs are observed near the equatorward edge of the gap. An important result is that the overall sequence of VDIS-gap-CPS can be explained in terms of orbital dynamics in the tail. The gap in precipitation appears as the counterpart of the 'wall' regime in the equatorial plane, in which a cross-tail current carried by energetic ions is strongly enhanced between 8 and 12 R(E). This region has important consequences for the development of substorms.

  3. Transient composite electric field disturbances near dip equator associated with auroral substorms

    SciTech Connect

    Hanumath Sastri, J.; Ramesh, K.B.; Ranganath Rao, H.N. )

    1992-07-24

    Ionosonde data of Kodaikanal and Huancayo are used to show the simultaneous occurrence of a transient disturbance in F region height of composite polarity in day and night sectors near the dip equator during the auroral substorm activity on 20 August 1979. At Kodaikanal which is on the nightside at the time of the substorm activity, h[prime]F first underwent an abrupt and rapid decrease (80km in 1 hr) followed by a much larger increase (120km in 1 hr). Perturbation in hpF2 of exactly opposite polarity was simultaneously seen at Huancayo which is on the dayside. The decrease in h[prime]F at Kodaikana (increase in hpF2 at Huancayo) occurred in association with an increase in polar cap potential drop, [phi] (estimated from IMF parameters), and the subsequent increase (decrease at Huancayo) with a decrease in polar cap potential. The F-region height disturbance is interpreted as the manifestation of a global transient composite disturbance in equatorial zonal electric field caused by the prompt penetration of substorm-related high latitude electric fields into the equatorial ionosphere. The polarity pattern of the electric field disturbance is consistent with the global convection models which predict westward (eastward) electric fields at night (by day) near the geomagnetic equator in response to an increase in polar cap potential drop, and fields of opposite signs for a decrease in polar cap potential.

  4. Automatic Georeferencing of Astronaut Auroral Photography: Providing a New Dataset for Space Physics

    NASA Astrophysics Data System (ADS)

    Riechert, Maik; Walsh, Andrew P.; Taylor, Matt

    2014-05-01

    Astronauts aboard the International Space Station (ISS) have taken tens of thousands of photographs showing the aurora in high temporal and spatial resolution. The use of these images in research though is limited as they often miss accurate pointing and scale information. In this work we develop techniques and software libraries to automatically georeference such images, and provide a time and location-searchable database and website of those images. Aurora photographs very often include a visible starfield due to the necessarily long camera exposure times. We extend on the proof-of-concept of Walsh et al. (2012) who used starfield recognition software, Astrometry.net, to reconstruct the pointing and scale information. Previously a manual pre-processing step, the starfield can now in most cases be separated from earth and spacecraft structures successfully using image recognition. Once the pointing and scale of an image are known, latitudes and longitudes can be calculated for each pixel corner for an assumed auroral emission height. As part of this work, an open-source Python library is developed which automates the georeferencing process and aids in visualization tasks. The library facilitates the resampling of the resulting data from an irregular to a regular coordinate grid in a given pixel per degree density, it supports the export of data in CDF and NetCDF formats, and it generates polygons for drawing graphs and stereographic maps. In addition, the THEMIS all-sky imager web archive has been included as a first transparently accessible imaging source which in this case is useful when drawing maps of ISS passes over North America. The database and website are in development and will use the Python library as their base. Through this work, georeferenced auroral ISS photography is made available as a continously extended and easily accessible dataset. This provides potential not only for new studies on the aurora australis, as there are few all-sky imagers in

  5. Steps toward validity in active living research: research design that limits accusations of physical determinism.

    PubMed

    Riggs, William

    2014-03-01

    "Active living research" has been accused of being overly "physically deterministic" and this article argues that urban planners must continue to evolve research and address biases in this area. The article first provides background on how researchers have dealt with the relationship between the built environment and health over years. This leads to a presentation of how active living research might be described as overly deterministic. The article then offers lessons for researchers planning to embark in active-living studies as to how they might increase validity and minimize criticism of physical determinism.

  6. Poleward arcs of the auroral oval during substorms and the inner edge of the plasma sheet

    NASA Astrophysics Data System (ADS)

    Haerendel, Gerhard

    2009-06-01

    An analytical model for the connection between the near-Earth edge of the plasma sheet at substorm onset and the auroral arcs at the poleward edge of the auroral oval is presented. The connection is established through the existence of a Boström type I current system. Its generator is assumed to be constituted by a narrow high-beta plasma layer located at the interface between the near-Earth plasma sheet and the outer edge of the near-dipolar field of the magnetosphere. The energy balance between the downward Poynting flux and the energy conversion in the auroral acceleration region and ionosphere provides a relation for the electric fields as a function of the upward field-aligned current. Only the upward current region is being considered in this work. An interesting effect, incorporated in the energy balance, is the feedback of the auroral electrojet on the magnetospheric plasma by dragging the latter eastward from below under the action of a Hall generator. Thereby a relation arises between the westward electric field, tangential to the arc, and the equatorward polarization field. Quantitative solution of the energy equation is achieved by using the empirical relations between auroral energy flux and electron energy and the integrated Hall and Pedersen conductivities. Accommodation of the downward energy flux requires the existence of a minimum arc length. The resulting quantities are consistent with typical auroral data sets. Relating the downward energy flux to the parameters of the generator reveals a strong dependence of polarization electric field, overall energy dissipation, and total current strength on the plasma beta of the generator. The dumping of excess energy from the high-beta plasma layer into the auroral arc(s) allows the stretched tail field lines to transform into dipolar field lines. It opens, so-to-speak, the gate into the outer magnetosphere.

  7. VISIONS: Combined remote sensing and in situ observations of auroral zone ion outflow during a substorm

    NASA Astrophysics Data System (ADS)

    Rowland, D. E.; Clemmons, J. H.; Hecht, J. H.; Lemon, C. L.; Collier, M. R.; Keller, J. W.; Pfaff, R. F.; Klenzing, J.; McLain, J.

    2013-12-01

    measured electric fields (DC through HF), magnetic fields, and electron temperature and density Taken together, these measurements provide important new information, previously available only through synoptic studies and long-term statistical databases, about the parameters that drive ion outflow most effectively. VISIONS flew through and near several regions of enhanced auroral activity, and also sensed regions of ion outflow both remotely (via ENA imaging) and directly (using in situ measurements). The combination of these measurements shows a strong correlation between regions of enhanced soft electron precipitation and enhanced ion outflow, and shows that the regions with enhanced ion outflow are spatially and temporally coherent, allowing VISIONS to set constraints on models of ion outflow, including spatial size, total ion outflow rates, and lifetime. In addition, VISIONS gives some information about the vertical profile of ENA emissions, from which ion energization profiles can be inferred. ENAs are mostly observed coming up from below the rocket, consistent with either low-altitude (300-400 km) transverse acceleration and/or a 'pressure cooker' mechanism.

  8. Non-triggered auroral substorms and long-period (1-4 mHz) geomagnetic and auroral luminosity pulsations in the polar cap

    NASA Astrophysics Data System (ADS)

    Yagova, Nadezda; Nosikova, Natalia; Baddeley, Lisa; Kozyreva, Olga; Lorentzen, Dag A.; Pilipenko, Vyacheslav; Johnsen, Magnar G.

    2017-03-01

    A study is undertaken into parameters of the polar auroral and geomagnetic pulsations in the frequency range 1-4 mHz (Pc5/Pi3) during quiet geomagnetic intervals preceding auroral substorms and non-substorm background variations. Special attention is paid to substorms that occur under parameters of the interplanetary magnetic field (IMF) conditions typical for undisturbed days (non-triggered substorms). The spectral parameters of pulsations observed in auroral luminosity as measured by a meridian scanning photometer (Svalbard) in the polar cap and near the polar boundary of the auroral oval are studied and compared with those for the geomagnetic pulsations measured by the magnetometer network IMAGE in the same frequency range. It is found that Pc5/Pi3 power spectral density (PSD) is higher during pre-substorm time intervals than for non-substorm days and that specific variations of pulsation parameters (substorm precursors) occur during the last 2-4 pre-substorm hours.

  9. Relationships between Interlibrary Loan and Research Activity in Canada

    ERIC Educational Resources Information Center

    Duy, Joanna; Larivière, Vincent

    2014-01-01

    Interlibrary Loan borrowing rates in academic libraries are influenced by an array of factors. This article explores the relationship between interlibrary loan borrowing activity and research activity at 42 Canadian academic institutions. A significant positive correlation was found between interlibrary loan borrowing activity and measures of…

  10. Sounding-Rocket Studies of Langmuir-Wave Microphysics in the Auroral Ionosphere

    NASA Astrophysics Data System (ADS)

    Dombrowski, Micah P.

    Since their discovery in laboratory plasmas in the 1920s, Langmuir waves have been observed to be ubiquitous in plasma environments, particularly in space plasmas. From the greater solar wind to planetary foreshocks and the auroral ionosphere, Langmuir waves are a key factor mediating electron temperature, and controlling electron beam propagation and beam-plasma energy transfer. Because they are so important, Langmuir waves in the space environment have been intensively investigated; however, there remain two challenging types of experiments that are relatively lacking: three-dimensional measurements of Langmuir-wave fields, and measurements of Langmuir wave-electron correlations. This thesis works on filling these two gaps, plus development of new Langmuir-wave instrumentation. The CHARM-II wave-particle Correlator instrument was designed to study the energy transfer between electron beams and plasmas via the sorting of incoming particles by concurrent Langmuir-wave phase, allowing for direct observation of electron bunching. Data from the CHARM-II sounding rocket comprises the first such observations with statistical levels of events, revealing an association between the polarity of the resistive component of the electron phase-bunching and changes in the electron flux at the associated energy, such that a negative resistive component goes with an increase in electron flux, and vice versa, effectively showing energy flow from the beam to the waves, and subsequent enhancements of wave damping. Surprisingly, the results also show comparable amounts of resistive and reactive activity. A test-particle simulation was developed to confirm the details of the theoretical explanation for the observed effect. A three-dimensional Langmuir-wave receiver flown on the TRICE sounding rocket mission reveals the beat signature of the amplitude-modulated 'bursty' form of Langmuir waves which has been observed in many environments. An analysis of the three-dimensional data shows

  11. Research on an Active Seat Belt System

    NASA Astrophysics Data System (ADS)

    Kawashima, Takeshi

    In a car crash, permanent injury can be avoided if deformation of an occupant's rib cage is maintained within the allowable value. In order to realize this condition, the occupant's seat belt tension must be instantaneously adjusted by a feedback control system. In this study, a seat belt tension control system based on the active shock control system is proposed. The semi-active control law used is derived from the sliding mode control method. One advantage of this proposed system is that it does not require a large power actuator because the seat belt tension is controlled by a brake mechanism. The effectiveness is confirmed by numerical simulation using general parameters of a human thorax and a passenger car in a collision scenario with a wall at a velocity of 100 km/h. The feasibility is then confirmed with a control experiment using a scale model of about 1/10 scale. The relative displacement of the thorax model approaches the allowable value smoothly along the control reference and settles near this value. Thus, the proposed seat belt tension control system design is established.

  12. Zoo visitors' understanding of terms denoting research activity.

    PubMed

    Carson, Lloyd

    2014-07-01

    Zoos have increasingly sought to justify their existence by reference to a scientific role particularly in the domains of animal welfare and conservation. Given recent initiatives by the UK government to foster public engagement with science, it is timely to investigate public attitudes towards primary research activity by zoos. This study reports the views of 83 visitors to Edinburgh Zoo. Within certain items in a structured interview noun terms denoting research activity were manipulated ("research" versus "studies") as was their qualification (adjective "scientific" present or absent before the noun term). "Research" was associated with a restricted and negative perception of investigatory activity. This effect was intensified when the noun term was preceded by "scientific". It is concluded that there is a continuing need to challenge public perceptions, particularly of the phrase "scientific research"; that in the meantime zoos should perhaps exercise caution when using it in relation to their activities.

  13. Radar auroral observations during a burst of irregular magnetic pulsations

    SciTech Connect

    Haldoupis, C.I.; Nielsen, E.; Holtet, J.A.; Egeland, A.; Chivers, H.A.

    1982-03-01

    Micropulsation data from an auroral state are compared with concurrent STARE radar observations from the E region above the station during a substorm event. The substorm onset is marked by a strong burst of irregular pulsations, (Pi B) accompanied by abrupt intensifications in the equivalent current, the backscatter intensity, and the riometer absorption. The magnetic Px and Py pulsation components have a reasonable degree of correlation and the polarization properties of the horizontal disturbance vetor exhibit well-defined changes during the first few minutes after onset. The radio signal undergoes deep quasiperiodic fading that is closely related to simultaneous PiB amplitude variations. The radar Dopplar data, which show normal fluctuations in the electron drift velocity, exclude modulation of radio backscatter by directional variations of the electric field. It is argued that the PiB pulsations and the variations seen in the backscatter are reflecting changes of the ionospheric currents due to conductivity modifications dictated by variations in the field-aligned currents flowing in the region. The possibility exists that the Pi B is closely related to precipitation pulsations as reported by Heacock and Hunsucker (1977).

  14. Laboratory Reproduction of Auroral Magnetospheric Radio Wave Sources

    SciTech Connect

    Ronald, K.; Speirs, D. C.; McConville, S. L.; Gillespie, K. M.; Phelps, A. D. R.; Cross, A. W.; Robertson, C. W.; Whyte, C. G.; He, W.; Bingham, R.; Vorgul, I.; Cairns, R. A.; Kellett, B. J.

    2008-10-15

    Auroral Kilometric Radiation, AKR, occurs naturally in the polar regions of the Earth's magnetosphere where electrons are accelerated by electric fields into the increasing planetary magnetic dipole. Here conservation of the magnetic moment converts axial to rotational momentum forming a horseshoe distribution in velocity phase space. This distribution is unstable to cyclotron emissions and radiation is emitted in the X-mode. In the laboratory a 75-85kV electron beam of 5-40A was magnetically compressed by a system of solenoids. Results are presented for an electron beam gyrating at cyclotron frequencies of 4.42GHz and 11.7GHz resonating with near cut-off TE01 and TE03 modes respectively. Measurements of the electron transport combined with numerical simulations demonstrated that a horseshoe distribution function was formed in electron velocity space. Analysis of the experimental measurements allowed the inference of the 1D number density as a function of the electron beam pitch angle. The total power emitted experimentally was {approx}19-35 kW with a maximum RF emission efficiency of {approx}2%. These results were compared to those obtained numerically using a 2D PiC code KARAT with a maximum efficiency of 2% predicted for the same mode and frequency, consistent with astrophysical and theoretical results.

  15. Effects of auroral potential drops on plasma sheet dynamics

    NASA Astrophysics Data System (ADS)

    Xi, Sheng; Lotko, William; Zhang, Binzheng; Wiltberger, Michael; Lyon, John

    2016-11-01

    The reaction of the magnetosphere-ionosphere system to dynamic auroral potential drops is investigated using the Lyon-Fedder-Mobarry global model including, for the first time in a global simulation, the dissipative load of field-aligned potential drops in the low-altitude boundary condition. This extra load reduces the field-aligned current (j||) supplied by nightside reconnection dynamos. The system adapts by forcing the nightside X line closer to Earth, with a corresponding reduction in current lensing (j||/B = constant) at the ionosphere and additional contraction of the plasma sheet during substorm recovery and steady magnetospheric convection. For steady and moderate solar wind driving and with constant ionospheric conductance, the cross polar cap potential and hemispheric field-aligned current are lower by approximately the ratio of the peak field-aligned potential drop to the cross polar cap potential (10-15%) when potential drops are included. Hemispheric ionospheric Joule dissipation is less by 8%, while the area-integrated, average work done on the fluid by the reconnecting magnetotail field increases by 50% within |y| < 8 RE. Effects on the nightside plasma sheet include (1) an average X line 4 RE closer to Earth; (2) a 12% higher mean reconnection rate; and (3) dawn-dusk asymmetry in reconnection with a 17% higher rate in the premidnight sector.

  16. [Activities of Bay Area Research Corporation

    NASA Technical Reports Server (NTRS)

    2003-01-01

    During the final year of this effort the HALFSHEL code was converted to work on a fast single processor workstation from it s parallel configuration. This was done because NASA Ames NAS facility stopped supporting space science and we no longer had access to parallel computer time. The single processor version of HALFSHEL was upgraded to address low density cells by using a a 3-D SOR solver to solve the equation Delta central dot E = 0. We then upgraded the ionospheric load packages to provide a multiple species load of the ionosphere out to 1.4 Rm. With these new tools we began to perform a series of simulations to address the major topic of this research effort; determining the loss rate of O(sup +) and O2(sup +) from Mars. The simulations used the nominal Parker spiral field and in one case used a field perpendicular to the solar wind flow. The simulations were performed for three different solar EUV fluxes consistent with the different solar evolutionary states believed to exist before today. The 1 EUV case is the nominal flux of today. The 3 EUV flux is called Epoch 2 and has three times the flux of todays. The 6 EUV case is Epoch 3 and has 6 times the EUV flux of today.

  17. The charged-particle fluxes at auroral and polar latitudes and related low-frequency auroral kilometric radiation-type and high-frequency wideband emission

    NASA Astrophysics Data System (ADS)

    Shutte, N.; Prutensky, I.; Pulinets, S.; Kløos, Z.; Rothkaehl, H.

    1997-02-01

    The results of simultaneous observations of charged particle fluxes within the energy range 50 eV to 20 keV (plasma energy-angle spectrometer, PEAS experiment) and plasma waves within the frequency range 0.1 to 10 MHz (plasma radio spectrometer, PRS 3 experiment) on board the APEX spacecraft are presented. The data were obtained at polar and auroral latitudes in the dawn-dusk and noon-midnight time sectors. The low-frequency (LF) sporadic emission mainly on frequencies lower than the local gyrofrequency was commonly observed within a comparatively narrow latitude interval (~5°-6°) of the auroral oval. The maximum of spectral wave intensity was revealed at a frequency of ~200kHz. The sporadic character of the observed emissions, the spectra, are very similar to those reported for auroral kilometric radiation (AKR), and the temporal and spatial occurrences imply its relation to the source of AKR emissions measured at the higher altitudes, with regards to our wave measurements as LF AKR-type emissions. Comparative analysis of spatial distributions of charged particle energy spectra and variations of wave spectra at auroral oval latitudes showed that several conditions should be fulfilled for LF AKR generation. These conditions are related both to the intensity and energy of precipitating ion and electron fluxes, and to albedo electrons and the ionospheric plasma parameters. The wideband HF emission was observed together with the LF AKR-type emission during the morning auroral oval crossing. At spacecraft apogee altitudes, in the polar cap zone intense electron precipitations and an increase of plasma noise intensity at frequencies equal or below fHe were observed at the period when the IMF was northward. These precipitations and emissions were accompanied by the horizontal currents crossing the polar cap, the so-called theta structure.

  18. Nursing research on physical activity: a feminist critique.

    PubMed

    Im, E

    2001-04-01

    Studies on physical activity have rarely included women as research participants, and have been mainly conducted among Western populations. In this paper, nursing research on women's physical activity is analyzed and critiqued using a feminist perspective that respects and values women's own experiences and their diversities. An extensive literature search was conducted using computerized data retrieval systems and 47 empirical studies published in nursing literature were selected and analyzed. The critique is presented with three main themes emerged from the analysis: (a) "without considering women's own experiences"; (b) "implicit androcentric and ethnocentric assumptions"; (c) "without meaningful interactions". Based on the analysis, future directions for nursing research on physical activity are proposed.

  19. A Comparison of Modeled Auroral Boundaries with Observations from Citizen Scientists

    NASA Astrophysics Data System (ADS)

    Case, N.; MacDonald, E.; Viereck, R. A.

    2015-12-01

    Over the past year, the citizen science project Aurorasaurus has collected new, globally-distributed, ground-based observations of the aurora and has integrated them with space-based estimates of auroral activity. A case study of these observations were compared to the OVATION Prime model of aurora, run by the NOAA Space Weather Prediction Center (SWPC). The observations were comprised of positive and negative sightings directly reported to Aurorasaurus, along with verified tweets, which are positive sightings reported on Twitter and verified by Aurorasaurus users. The observations were collected during March and April 2015, a period spanning three large geomagnetic storms, and covered a wide range of latitudes. The observations demonstrated that, during these events, over 60% of the positive aurora observations (which includes those reported directly to Aurorasaurus and the verified tweets) occurred at latitudes equatorward of the SWPC predicted "view line". New scaling parameters were determined from the relationship of the differences in latitude between the positive observations and the view line, and the maximum probability of visible aurora. Future work testing these scaling parameters and using them in the Aurorasaurus real-time alert system will be presented.

  20. Midday auroral observations in the oval, cusp region, and polar cap.

    NASA Technical Reports Server (NTRS)

    Romick, G. J.; Brown, N. B.

    1971-01-01

    Evaluation of combined photographic and photometric measurements made on the 1969 NASA airborne expedition, yielding a description of the midday oval, cusp region, and polar cap auroral precipitation at low magnetic activity (Kp = 0, 1+). The observations delineate three regions through the description of the type of aurora observed and the photometrically inferred change in energy of the particles: (1) the region in and equatorward of the oval where greater than 3-keV electrons are associated with 6300 A/4278 A ratios less than or equal to 1 and with a diffuse glow or structured arcs; (2) the cusp region where electrons of several hundred electron volts and spikes of more energetic electrons are associated with 6300 A/4278 A ratios between 10 and 35 in broken, fragmented, rayed features and patches; (3) the polar cap where discrete earth-sun-aligned arcs have height luminosity profiles in 5577 A, 6300 A (forbidden O I), and 4278 A (N2(+)) that suggest incoming electrons with an energy spectrum of 2-keV characteristic energy above a low-energy (few hundred electron volts) background.

  1. Ground-based observations of MF/HF radio noise in the auroral zone

    SciTech Connect

    Weatherwax, A.T.; LaBelle, J.; Trimpi, M.L.; Brittain, R.; Treumann, R.A.

    1994-02-01

    Broadband noise enhancements in the frequency range of {approximately} 1.4-4.8 MHz have been observed with a ground-based receiver located at Two Rivers, Alaska (near Fairbanks). During the 5-month period from November 1991 to March 1992, eight broadband noise enhancements were recorded. A correlation is observed between the radio noise enhancements and magnetic activity recorded with the magnetometer in College, Alaska (45 km away). Initial examination of college ionosonde data also suggest that sporadic E is associated with the termination of some of the events. The enhancements are characterized by a low-frequency cutoff at {approximately} 1.4 MHz and a decrease in intensity near {approximately} 2.8 MHz, which roughly correspond to 1 and 2 times the ionospheric electron cyclotron frequency, respectively. Although some discrete man-made signals are observed to be enhanced during the events, the bulk of the broadband enhancements may be composed of natural signals. If natural, the observed spectral shape is consistent with calculations of synchrotron radiation combined with cyclotron absorption; in this case, these signals would be diagnostic of the hardness of the auroral electron energy spectrum. 26 refs., 9 figs.

  2. Anomalous ISR echoes preceding auroral breakup: Evidence for strong Langmuir turbulence

    NASA Astrophysics Data System (ADS)

    Akbari, H.; Semeter, J. L.; Dahlgren, H.; Diaz, M.; Zettergren, M.; Strømme, A.; Nicolls, M. J.; Heinselman, C.

    2012-02-01

    Experimental results obtained with the 449-MHz Poker Flat Incoherent Scatter Radar (PFISR) show unusual features in both the ion line and plasma line measurements during an auroral breakup event. The features are a greatly enhanced flat ion acoustic spectrum (believed to indicate the presence of an additional peak at zero Doppler), and two peaks in the plasma line spectrum. Similar spectral morphologies are observed during active HF ionospheric modification experiments and are considered unmistakable indications of Strong Langmuir Turbulence (SLT). In SLT theory, the central peak in ion acoustic spectrum is caused by Bragg scattering from non-propagating density fluctuations (cavitons), and the two peaks in the plasma line spectrum are associated with (1) Langmuir waves trapped in the cavitons, at the cold plasma frequency, and (2) a “free mode” at the Langmuir frequency. Free modes are radiated Langmuir waves from collapsing cavitons that follow the linear dispersion relation. The observed turbulence was confined to a thin layer (˜10-km) centered at ˜230 km altitude.

  3. Ion acceleration by Alfvén waves on auroral field lines

    NASA Astrophysics Data System (ADS)

    Bingham, Robert; Eliasson, Bengt; Tito Mendonça, José; Stenflo, Lennart

    2013-05-01

    Observations of ion acceleration along auroral field lines at the boundary of the plasma sheet and tail lobe of the Earth show that the energy of the ions increases with decreasing density. The observations can be explained by ion acceleration through Landau resonance with kinetic Alfvén waves (KAWs) such that kA·vi = ωA, where kA is the wave vector, vi is the ion resonance velocity and ωA is the Alfvén wave frequency. The ion resonance velocities are proportional to the Alfvén velocity which increases with decreasing density. This is in agreement with the data if the process is occurring at the plasma sheet tail lobe boundary. A quasi-linear theory of ion acceleration by KAWs is presented. These ions propagate both down towards and away from the Earth. The paths of the Freja and Polar satellites indicate that the acceleration takes place between the two satellites, between 1Re and 5Re. The downward propagating ions develop a horseshoe-type of distribution which has a positive slope in the perpendicular direction. This type of distribution can produce intense lower hybrid wave activity, which is also observed. Finally, the filamentation of shear Alfvén waves is considered. It may be responsible for large-scale density striations. In memory of Padma Kant Shukla, a great scientist and a good friend.

  4. Features of the planetary distribution of auroral precipitation characteristics during substorms

    NASA Astrophysics Data System (ADS)

    Vorobjev, V. G.; Yagodkina, O. I.; Starkov, G. V.; Feldstein, Ya. I.

    2007-04-01

    A planetary pattern of substorm development in auroral precipitation has been constructed on the basis of the F6 and F7 satellite observations. The behavior of the auroral injection boundaries and characteristics of precipitating electrons in various precipitation regions during all phases of a statistically mean magnetospheric substorm with an intensity of AL ˜ -400 nT at a maximum is considered in detail. It is shown that during a substorm, the zone of structured auroral oval precipitation AOP and the diffuse auroral zone DAZ are the widest in the nighttime and daytime sectors, respectively. In the daytime sector, all precipitation regions synchronously shift equatorward not only at the origination phase but during the substorm development phase. The strongest shift to low latitudes of the daytime AOP region is observed at a maximum of the development phase. As a result of this shift, the area of the polar cap increases during the phases of substorm origination and development. It is shown that the average position of the precipitation boundaries and the energy fluxes of precipitating electrons at each phase are linearly related to the intensity of a magnetic disturbance. This makes it possible to develop a model of auroral precipitation development during each phase of substorms of any intensity.

  5. Simulation of ion cyclotron heating in the auroral current region in the VASIMR

    NASA Astrophysics Data System (ADS)

    Bering, E. A.; Chang-Diaz, F. R.; Squire, J. P.; Brukardt, M.; Glover, T. W.; Bengtson, R. D.; Jacobson, V. T.; McCaskill, G. E.; Cassady, L.

    Plasma physics has found an increasing range of practical industrial applications including the development of electric spacecraft propulsion systems One of these systems the Variable Specific Impulse Magnetoplasma Rocket VASIMR engine both applies and can be used to simulate several important physical processes occurring in the magnetosphere These processes include the mechanisms involved in the ion acceleration and heating that occur in the Birkeland currents of an auroral arc system Auroral current region processes that are simulated in VASIMR include lower hybrid heating parallel electric field acceleration and ion cyclotron acceleration This paper will focus on using a physics demonstration model VASIMR to study ion cyclotron heating ICRH similar to auroral zone processes The production of upward moving ion conics and ion heating are significant features in auroral processes It is believed that ion cyclotron heating plays a role in these processes but laboratory simulation of these auroral effects is difficult owing to the fact that the ions involved only pass through the acceleration region once In the Variable Specific Impulse Magnetoplasma Rocket VASIMR we have successfully simulated these effects The current configuration of the VASIMR uses a helicon antenna with up to 20 kW of power to generate plasma then uses an RF booster stage that uses left hand polarized slow mode waves launched from the high field side of the resonance The current setup for the booster uses 2 to 4 MHz waves with up to 20 kW of power This is

  6. Statistical study of the GNSS phase scintillation associated with two types of auroral blobs

    NASA Astrophysics Data System (ADS)

    Jin, Yaqi; Moen, Jøran I.; Miloch, Wojciech J.; Clausen, Lasse B. N.; Oksavik, Kjellmar

    2016-05-01

    This study surveys space weather effects on GNSS (Global Navigation Satellite System) signals in the nighttime auroral and polar cap ionosphere using scintillation receivers, all-sky imagers, and the European Incoherent Scatter Svalbard radar. We differentiate between two types of auroral blobs: blob type 1 (BT 1) which is formed when islands of high-density F region plasma (polar cap patches) enter the nightside auroral oval, and blob type 2 (BT 2) which are generated locally in the auroral oval by intense particle precipitation. For BT 1 blobs we have studied 41.4 h of data between November 2010 and February 2014. We find that BT 1 blobs have significantly higher scintillation levels than their corresponding polar cap patch; however, there is no clear relationship between the scintillation levels of the preexisting polar cap patch and the resulting BT 1 blob. For BT 2 blobs we find that they are associated with much weaker scintillations than BT 1 blobs, based on 20 h of data. Compared to patches and BT 2 blobs, the significantly higher scintillation level for BT 1 blobs implies that auroral dynamics plays an important role in structuring of BT 1 blobs.

  7. Survey of research activity among multidisciplinary health professionals.

    PubMed

    Marshall, Andrea P; Roberts, Shelley; Baker, Mark J; Keijzers, Gerben; Young, Jessica; Stapelberg, N J Chris; Crilly, Julia

    2016-02-01

    Objective The aim of the present study was to describe the research activities being undertaken by health service employees within one Australian health service and explore their experiences with undertaking research.Methods The present mixed-methods study was conducted across one health service in Queensland, Australia, and included a cross-sectional online survey and interviews with healthcare service employees. The anonymous survey was a self-administered online questionnaire, distributed to all 6121 employees at the health service via email, asking about research activity and engagement. Willing participants were also interviewed on their perceptions and experiences with research and capacity building.Results In all, 151 participants responded to the survey and 22 participated in interviews. Three-quarters of respondents reported actively participating in research over the past 6 years and several research outputs, such as publications, conference presentations and competitive grant funding, were displayed. Four concepts emerged from interview findings, namely collaborative partnerships, skilled mentorship, embedding research and organisational support, which represented the overall theme 'opportunities for a research-infused health service'.Conclusion Employees of the health service recognised the importance of research and had a range of research skills, knowledge and experience. They also identified several opportunities for building research capacity in this service.What is known about the topic? Building research capacity among healthcare professionals is important for enabling the conduct of high-quality research in healthcare institutions. However, building research capacity is complex and influenced by the uniqueness of organisational context. In order to successfully build research capacity among employees at any health service, current research activity, skills and experience, as well as staff perceptions around building research capacity in that

  8. Research on substances with activity against orthopoxviruses.

    PubMed

    Kołodziej, Marcin; Joniec, Justyna; Bartoszcze, Michał; Gryko, Romuald; Kocik, Janusz; Knap, Józef

    2013-01-01

    Although smallpox was eradicated over 30 years ago, the disease remains a major threat. High mortality, high infectivity and low resistance of the contemporary population make the smallpox virus very attractive to terrorists. The possible presence of illegal stocks of the virus or risk of deliberate genetic modifications cause serious concerns among experts. Hence, it is reasonable to seek effective drugs that could be used in case of smallpox outbreak. This paper reviews studies on compounds with proven in vitro or in vivo antipoxviruses potential, which show various mechanisms of action. Nucleoside analogues, such as cidofovir, can inhibit virus replication. Cidofovir derivatives are developed to improve the bioavailability of the drug. Among the nucleoside analogues under current investigation are: ANO (adenozine N1-oxide) and its derivatives, N-methanocarbothymidine [(N)-MCT], or derivatitives of aciklovir, peninclovir and brivudin. Recently, ST-246 - which effectively inhibits infection by limiting release of progeny virions - has become an object of attention. It has been also been demonstrated that compounds such as: nigericin, aptamers and peptides may have antiviral potential. An interesting strategy to fight infections was presented in experiments aimed at defining the role of individual genes (E3L, K3L or C6L) in the pathogenesis, and looking for their potential blockers. Additionally, among substances considered to be effective in the treatment of smallpox cases, there are factors that can block viral inhibitors of the human complement system, epidermal growth factor inhibitors or immunomodulators. Further studies on compounds with activity against poxviruses are necessary in order to broaden the pool of available means that could be used in the case of a new outbreak of smallpox.

  9. Research Active Programme: A Pilot Inclusive Research Curriculum in Higher Education

    ERIC Educational Resources Information Center

    Salmon, Nancy; García Iriarte, Edurne; Burns, Emma Q.

    2017-01-01

    Participation of people with disabilities in producing and using research is critical for monitoring the implementation of the United Nations Convention on the Rights of Persons with Disabilities (CRPD). The Research Active Programme (RAP) is a module designed to build research capacity of students with intellectual disabilities. RAP was…

  10. How the Doctorate Contributes to the Formation of Active Researchers: What the Research Tells Us

    ERIC Educational Resources Information Center

    Sinclair, Jennifer; Barnacle, Robyn; Cuthbert, Denise

    2014-01-01

    While much research focuses on factors contributing to doctoral completion, few studies explore the role of the doctorate in forming active researchers with the skills, know-how and appetite to pursue research post-completion. This article investigates 15 existing studies for evidence of what factors in the doctoral experience may contribute to…

  11. Bling My Research! A Mock Grant Panel Activity Illustrating the Importance of Basic Research

    ERIC Educational Resources Information Center

    Leander, Celeste A.; Whitton, Jeannette

    2010-01-01

    First-year university students have misconceptions about the source and dynamics of publicly funded research money. We designed an activity in which students take part in a mock grant panel. The results indicated a strong tendency toward student funding of applied medical research at the expense of basic research. Exposure to a few examples of…

  12. Space Research, Education, and Related Activities in the Space Sciences

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Universities Space Research Association received an award of Cooperative Agreement #NCC5-356 on September 29, 1998. The mission of this activity, know as the Cooperative Program in Space Sciences (CPSS), is to conduct space science research and leading-edge instrumentation and technology development, enable research by the space sciences communities, and to expedite the effective dissemination of space science research, technology, data, and information to the educational community and the general public. To fulfill this mission, USRA recruits and maintains a staff of scientific researchers, operates a series of guest investigator facilities, organizes scientific meetings and workshops, and encourages various interactions with students and university faculty members.

  13. Space Research, Education, and Related Activities in the Space Sciences

    NASA Technical Reports Server (NTRS)

    Black, David; Marshall, Frank (Technical Monitor)

    2002-01-01

    The Universities Space Research Association received an award of Cooperative Agreement NCC5-356 on September 29, 1998. The mission of this activity, known as the Cooperative Program in Space Sciences (CPSS), is to conduct space science research and leading-edge instrumentation and technology development, enable research by the space sciences communities, and to expedite the effective dissemination of space science research, technology, data, and information to the educational community and the general public. To fulfill this mission, USRA recruits and maintains a staff of scientific researchers, operates a series of guest investigator facilities, organizes scientific meetings and workshops, and encourages various interactions with students and university faculty members.

  14. Space Research, Education, and Related Activities In the Space Sciences

    NASA Technical Reports Server (NTRS)

    Black, David

    2002-01-01

    The mission of this activity, known as the Cooperative Program in Space Sciences (CPSS), is to conduct space science research and leading-edge instrumentation and technology development, enable research by the space sciences communities, and to expedite the effective dissemination of space science research, technology, data, and information to the educational community and the general public. To fulfill this mission, the Universities Space Research Association (USRA) recruits and maintains a staff of scientific researchers, operates a series of guest investigator facilities, organizes scientific meetings and workshops, and encourages various interactions with students and university faculty members. This paper is the final report from this now completed Cooperative Agreement.

  15. The phase speed of artificial field-aligned irregularities observed by CUTLASS during HF modification of the auroral ionosphere

    NASA Astrophysics Data System (ADS)

    Eglitis, P.; Robinson, T. R.; Rietveld, M. T.; Wright, D. M.; Bond, G. E.

    1998-02-01

    The RF heater facility at Ramfjordmoen, Tromsø can generate field-aligned plasma irregularities in the field of view of the Cooperative UK Twin-Located Auroral Sounding System (CUTLASS) coherent backscatter radar at Hankasalmi, Finland. In a recent set of experiments conducted in April 1996, the phase speed of the generated plasma irregularities has been compared with independent measurements of the plasma drift velocity observed by the European Incoherent Scatter radar facility. The phase speed of the plasma irregularities is found to be equal to the component of the plasma drift velocity in the direction of propagation of the plasma wave. This result is a further verification of the high performance of the CUTLASS radar and also demonstrates how artificially generated plasma irregularities can be employed to detect small plasma drift velocities and contribute to geophysical research. The characteristics of the Doppler spectrum of the artificial plasma waves are also described and discussed.

  16. Stable Auroral Red arc occurrences detected by the Pacific Northwest Laboratory photometer network: A decade of observations, 1978--1988

    SciTech Connect

    Slater, D.W.; Kleckner, E.W.

    1989-11-01

    Using data obtained from a network of all-sky scanning photometers designed to operate routinely for long periods of time, a comprehensive inspection of observations covering the time period 1978--1988 has revealed features that we interpret to be Stable Auroral Red (SAR) arcs during 250 nighttime observing periods. These arcs result from high temperature within the ionospheric electron gas that is maintained by slow leakage of energy from the earth's magnetosphere. A listing of these events, the most complete available for this time interval, is presented for the purpose of complementing observations reported for earlier dates. This listing is composed of location of the observing photometer, date, time, photometric intensity, and location (as defined by the earth's magnetic coordinate system). The intent is to make these observations available to a broad range of researchers and thereby initiate further investigations of these features. 22 refs., 3 figs., 2 tabs.

  17. Top 10 research questions related to children physical activity motivation.

    PubMed

    Chen, Ang

    2013-12-01

    Physical activity is critical to healthy development of children. It is well documented that helping children develop and sustain a physically active lifestyle requires children to become motivated. Many studies have been conducted in the past 2.5 decades on determinants and correlates for children and adolescents' physical activity motivation. The findings have informed researchers and practitioners about motivation sources for children and effective strategies to motivate children in given physical activity settings. Built on the extensive knowledge base and theoretical platforms formed by these research studies, the purpose of this article is to take a look at the current research landscape and provide subjective thoughts about what we still need to know about children's physical activity motivation. The product of this subjective thinking process rendered 10 potential questions for future research on children's physical activity motivation in both in-school and out-of-school settings. These topics encompass those focusing on children's physical activity motivation as a mental dispositional process, those conceptualizing the motivation as an outcome of person-environment interactions, and those attempting to dissect the motivation as an outcome of social-cultural influences and educational policies. It is hoped that the topics can serve researchers interested in children's physical activity motivation as starting blocks from which they can extend their conceptual thinking and identify research questions that are personally meaningful. It is also hoped that the list of potential questions can be helpful to researchers in accomplishing the imperative and significant mission to motivate children to be physically active in the 21st century and beyond.

  18. Comparative research on activation technique for GaAs photocathodes

    NASA Astrophysics Data System (ADS)

    Chen, Liang; Qian, Yunsheng; Chang, Benkang; Chen, Xinlong; Yang, Rui

    2012-03-01

    The properties of GaAs photocathodes mainly depend on the material design and activation technique. In early researches, high-low temperature two-step activation has been proved to get more quantum efficiency than high-temperature single-step activation. But the variations of surface barriers for two activation techniques have not been well studied, thus the best activation temperature, best Cs-O ratio and best activation time for two-step activation technique have not been well found. Because the surface photovoltage spectroscopy (SPS) before activation is only in connection with the body parameters for GaAs photocathode such as electron diffusion length and the spectral response current (SRC) after activation is in connection with not only body parameters but also surface barriers, thus the surface escape probability (SEP) can be well fitted through the comparative research between SPS before activation and SEP after activation. Through deduction for the tunneling process of surface barriers by Schrödinger equation, the width and height for surface barrier I and II can be well fitted through the curves of SEP. The fitting results were well proved and analyzed by quantitative analysis of angle-dependent X-ray photoelectron spectroscopy (ADXPS) which can also study the surface chemical compositions, atomic concentration percentage and layer thickness for GaAs photocathodes. This comparative research method for fitting parameters of surface barriers through SPS before activation and SRC after activation shows a better real-time in system method for the researches of activation techniques.

  19. [Research activities of cosmonauts in long-duration orbital missions].

    PubMed

    2012-01-01

    The paper presents the view of space medicine and human factor experts on the problems of cosmonaut's research activities. Readiness of ISS crewmembers for conducting experiments and research equipment handling depends on the pre-flight training quality and course of adaptation to the flight conditions, the latter of particular criticality for participation in human use tests as an object.

  20. RESEARCH ACTIVITIES AT THE US EPA'S GULF ECOLOGY DIVISION

    EPA Science Inventory

    The purpose of this talk was to present an overview of research activities at the US EPA's Office of Research and Development, Gulf Ecology Division located on Pensacola Beach, Florida. The talk was organized into three major sections. The first section covered my educational b...